Foodborne Inf & Intox
Foodborne Inf & Intox PHR 250
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Bacillus cereus Mehrdad Tajkarimi DVM PhD University of CaliforniaDavis PHR 250 07 MehrdadTalkanmi UCDavis VMPHR 25 7 Introduction 0 Grampositive sporeforming microorganism 0 At present three enterotoxins able to cause the diarrheal syndrome Hemolysin BL HBL nonhemolytic enterotoxin NHE and cytotoxin K HBL and NHE are threecomponent proteins Cytotoxin K is a single protein toxin MehmadTalkanm uc Davis VMPHR 25 n7 Introduction 0 Symptoms caused by the latter toxin are more severe and may even involve necrosis 0 In general the onset of symptoms is within 6 to 24 h after consumption of the incriminated food 0 B cereus food poisoning is underestimated probably because of the short duration of the illness 24 h MehrdadTalkanmi UCDavis VMPHR 25 7 History 0 First discovered in 1880 0 1950 many outbreaks from meat and vegetable soups cooked meat and poultry fish milk and ice cream were described in Europe 0 In 1969 the first wellcharacterized B cereus outbreak in the USA was documented MehmadTalkanm uc Davis VMPHR 25 n7 Best estimates of the annual cases and deaths caused by B cereus in the US Agent Cases Percent Deaths Percent B czrms 27360 02 0 0 Total 4175565 302 1297 717 bacterial Total 13814924 100 1809 100 foodborne MehrdadTalkanmi UCDavis VMPHR 25 n7 Classi cation of B cereus 0 The genus Badus presently divided into subgroups based on spore morphology 0 B cereus falls in the Bac17u5 subl is group and it is closely related to B anthracis B mycoides and Bt7urhgie75is 0 B cereusand B anthracis are both recognized as pathogens but the former is implicated with foodborne disease 5 anthracis can infect perorally but is inefficient MehmadTalkanm uc Davis VMPHR 25 n7 Criteria to differentiate among four closely related Bacillus spp Species Culnny Muijle Hemmde Swwm ity Paraspnml virulent mPenicillin Budy tnMice B re ux White Yes Yes N0 N0 No B an rmtix White N0 No Yes No Yes B mythe Rhizoid N0 N0 N0 N0 N0 5 WhliS Yes Yes No Yes No thuringiznsix Grey Mimi4T u H n VMPHR 25 n7 Factors Affecting Growth of B cereus IGrowth temperature 749 C with a minimum of 45 C maximum 48 50 C IGeneraIIy spore germination temperature range from 830 C I pH 4993 MahmadTaikaiim uc Davis VMPHR 25 n7 Factors Affecting Growth of B cereus I Water activity 091093 I Salt as high as 75 NaCI some tolerate 10 I D value for spores at 100 C around 3 min I The dose for 90 reduction of spores is 125 4kGy I 017065 kGy for vegetative cells MehidadTaikaiimi UCDavis VMPHR 25 n7 Name of Illness Caused by B cereus I The diarrhoeal syndrome is caused by enterotogtltins that are produced during growth of B cereusin the small intestine I The diarrheal illness more common in North America and Europe is caused by a high molecular weight prote39n I In some outbreaks there seems to be an overlap between the diarrheal and the emetic types of illness MEhidadTaikaiimi UCDavis VMPHR 25 n7 Name of Illness Caused by B cereus I B cereus has two recognized types of foodborne illness diarrheal emetic I The emetic syndrome is caused by cereulide a heat and pH stable peptide toxin I Consumption of food contaminated with this toxin may lead to emesis between 30 min and 5 h after ingestion MahmadTaikaiim uc Davis VMPHR 25 n7 Comparison of diarrheal and emetic types of B cereus food poisoning Syndrome Incubation Duration Dose Foods Diarrheal 816 h 1224 h 1037107 CFU Milk soup meat ingested producis puddings Emetic 175 h 1224 h min8 per g of Rice pa food noodles pastries Granum39 P E 1994 Mahmad Taikaiim UC Davis mm m in Which Food 0 Milk vegetables meat and fish 0 The emetic type of poisoning include rice products potato pasta and cheese products Mehrdad Tajkarimi uc Davis VMPHR 25D n7 Which Food 0 Other foods such as sauces pastries soups puddings and salads were identi ed as vehicles in food poisoning outbreaks Mahmad Taiiarimi uc Davis VMPHR 25D n7 Comparison of food ponsoning caused by different bacterial Pathngeh Incubntinn Ddrata39nh nf Dnmihata39hg Iype nf Frequently h 11hressh sighs Disease Duplicated Fund 5 cenzux 3715 12724 Diarrhea tnx jcir Meat rnducts diarrheai infectinn smips veganbles puddings and sauces a pelfringenx 3715 12724 Diarrhea s infectinn prnduets and gravy 5 was 175 12724 Diarrhea Ihtnxicatjnh Fried rice frnm emetic rairiy Chinese restaurants cnmmnn and ltake nutl shnps vnmitihg s mreux 175 12724 Diarrhea Ihtnxieatjnh Canked meats and Vn 39 ng pnllltry and dairy Gilbert R J arid Kramer JM 1987 Mehrdad Taikarimi UC Davis VMPHR 25D n7 Infective Dose oInfective dose of B cereus ranges from 104 to 1011 cells per gram of food ea Mahmad Taiiarimi uc Davis VMPHR 25D n7 Detection of B cereus 0 Blood agar can be used as a plating medium 0 Nutrient broth followed by blood agar useful for most probable number count Mehrdad Tajkarimi uc Davis VMPHR n n7 Prevention 0 Preventing contamination of food with its spores is almost impossible OInhibit spore germination and prevent the growth of vegetative cells in cooked readytoeat foods Mahmad Taiiarimi uc Davis MPH 25D n7 Listeria monocytogenes Adapted from Dr Harris s n tes I Introduction I General characteristics I Growth of Lm I Taxonomy and serology I Reservoirs I Listeriosis virulence factors and infectio I Out re s oflisteriosis Risk assessment and zero tolerance policy I Centre of m Intr IPathogen rst describe IBefore 1982 e recognized as a cause of abortions encephalitis in many animals panic arly cattle and sheep e thought to be associated with contamin animal feed or silage IIn1929LmWasreco 39 as acause of human illness I It Was until 1981 that a foodbo association Was Widely accepted IThe organism its epidemiology mechanisms ofviiul nce a o E a a been extensively reviewed General I Grampositive I Ovoid to rodshaped ht Mextbaaka aactznnla netListenan I Ubiquitous in the enviro I Facultative anaerobe I Acid but not gas producing fro glucose oan multiply at temperatures between 0 and 45 C 7 apsychrotroph o Relatively resistant to NaCl survival at 20 to 30 0 Can tolerate low pH 0 Not inhibited by carbon dioxide 0 Can survive many processing techniques such as freezing and drying wth at 10 Canadian Po39 on RTE Foods 0 RTE foods NOT supporting th monocytogenes include 7 water activity of S 092 regardless of 7 frozen foods Farber and Harwig 1996 Ta 0 GenusLiSteria munucymgenes u a gray o mmrayz zvanuvzz o L monocytogenes only species considered to be of public health signi cance L reeligeri and L ivanovii implicated in human infections on rare occassions Chknkwtuk R Q VT in Growth Charaderistics of Lm Limitrange Temp pH Water 0C ctivity Minimum 04 439 0 2 Optimum 37 70 Maximum 45 94 Growth at Lag and gene quot n times for Lrn using US DA P Temperature Lag time neration time 0C days m5 4 1249 6 891 8 646 10 476 12 356 14 271 16 209 mm 0 nTT activit of098 l o All serotypes may cause human 39 o 95 of human isolates r 12a12b or 4b 7 4b accounw for 33750 ofhuman listeriosi Worldwide and has been responsible for mos recorded foodborne outbreaks o L monocytogenes is ubiqu 7 decaying vegetation 7 soils potentially occur during refrigerated tar 7 animal and human feces and home storage SEW e 511 O Psychrotrophrc nature ofmo raises conc rn tg in refrigerated foods with extended shelf li Wa er o It has been isolated from a wide range of retail foods o 780 to 90 of listeriosis cases are 39 ingestion of contaminated food 7 pri foodborne host dependent 7 It is likely that lt1000 CFU is ofno c ncern to healthy adulm 7 ln susceptible persons this level is ass to cause illness 0 lmplicated products include soft cheeses meam and hot dogs 7 products that are refrigerated may have long shelf life and permit growth Vi rule 0 Smptoms 0 Intracellular parasite 7 Range from ulike to septicemia an 39 39 39 O Abnormalities in Tcell lymph 7 Listeriosis refers to the more serious life 39 immunity increase the risk of liste 39 o The Tcell response in the first few following infection is important to the subsequent outcome of the disease illness experienced by healthy 7 Pregnant Women newborns elderly and immunocompromised individuals are most susceptible and experience a more severe illness 7 Case fatality rates for these groups range from 13 3 4 0 Eight genes clustered on the chromosome are associated with virulence Peyer s patches 0 lnternalized by phagosomes 7 Surface proteins internalin and p60 though to aid internalization 0 Once internalized vacuole membrane lyse and mo released to cytoplasm Where multiplication occurs Macrophage avparenchymal well simian M long minim g t fnmuu nnn mdz m imm all a 9 p want in t Factors cell fan essential Virule I Lrn has the ability to spread cel component of viru en e I To accomplish this 7 Imuses the host ce11 actin machinery contin iist assenih1ing an acting tai1 at a pole ofthe hacten ce11 surface 7 rhe tai1 serves to propel the bacterium across cytoplasm pushing the oiganisin against the host ce1 7 A pmtnisicn is formed which can be ingested by an adjacent ce1 7 Three genes mpl MA and pm have been linked with process o Phagosomes are transported lymph nodes liver and spleen o Dissemination to brain placenta give v 39 forms of illness 0 Lm is able to cross the gastrointestinal matemofetal and bloodbmin protective barriers o Wellde ned highrisk group 7 Pregnant women neonates immunocompromised adults Illness caus 0 Types 7 Zoonotic infection 7 Infection during pregnancy listeri sis 7 Neonatal infection listeriosis 7 Infection of nonpregnant adults and children gt1 month listeriosis r Gastroenteritis Zoonotic fection 0 Local infection of the skin 0 Mild and selfresolving 0172 days Neonatal Ne rn Infection Olnfection of babies from mother crossinfection from other neonate ONeonatal listeriosis can be highly sev e 7 Sepsis pneumonia less than 7 days old 7 Meningitis sepsis greater than 7 days 7 Death 7 Vomiting and diarrhea 7 Can progress to bacteremia but usua selflimiting 7 Onset lt24 hr after consumption 7 Duration 12 days Listeriosis durl 0 Mother 7 Acquired following ingestion ofcontam39 e Asymptomatic ormild ulike illness 7 Serious complications for unbom Infant prete spontaneous abortion fetal death or stillbirth 0 Infection more common in 3rd trimester O Onset from 1 to several months 0 Pregnant Women Not more susceptible to most foodborne pathogens 0 Pregnancy leads to downregulation of cellular immunity pregnancy 0 Acquired following ingestion o taminated food 7 Asymptomatic or mild illness 7 Illness may progress to central nervous sys m infections such as meningitis 7 Most common in immunocompromised or eld 1y 7 Onset with 1 day or up to several months diabetes age kidney disease 0 Alcoholism cirrhosis conditions assoc ted with iron overload o Mild illness which can progress to nervous system infections meningitis Outbreaks of Lie Outbr o Mexicanstyle white cheese pH 0 Levels unknown 0 Serotype 4b 0 145 cases 64 deaths 0 Contributing factors environment and equi grossly contaminated raw milk deliveries exceeded pasteurization capacity 0 Control options Adequate pasteurization sanitation Outbr 0 Hot dogs and deli meats 89 state 22 0 Levels unknown 0 Over 100 people 15 deaths 6 miscarrr 0 Comments construction dust at the plan i believed to have contaminated the product n the packaging room 0 Control options Proper sanitation during packaging postpackaging pasteurization Outbr o Coleslaw 1981 Maritime Provin 0 Levels unknown 0 Serotype 4b 0 41 cases 18 deaths 2 adults and 16 fetalne born 0 Contributing factors Cabbage suspect contamina 39on fro uncomposted sheep manur Cabbaged stored before shredding 0 Control options apply good agricultural practices stomge lt1 C or lt10 ays Outbr 0 Chocolate milk 1995 Illinois 0 Levels 1077109 CFUml o 45 persons gastroenteritis o Outbreak strain found in tank drain and uno ened pack ofmilk Milk pasteurized then held Ja et blocked Cartons transported to picnic and held unrefrigerated several hours 0 Control options Equipment in good repair adequate sanitation temperature control 198687 CDC Case control stu 7 Hotdogs not reheated undercooked 0 198890 CDC Case control study 7 So cheese food from delicatessen count s undercooked po try Microbial Ecology of Foods Dean 0 Cliver A food is an ecosystem for microbes They don39t know they are in food Bacteria 8 molds may multiply survive or die A food is an ecosystem for microbes oViruses 8 parasites can only persist or be inactivated die lose infectivity oMost attention devoted to fates of bacterial pathogens l Dathogenic bacteria in food potential outcomes Persistence viable numbers unchanged lag or stationary phase or sporulation Growth multiplication rate parameter variable based on doubling time Pathogenic bacteria in food potential outcomes oDeath another rate parameter cf viablenonculturable oSporulation another defense species oToxigenesis growth is necessary but possibly not Growth curve biology Spores 8 lag phase cells quiescent adaptation to environmental conditions selecting needed enzymes activating appropriate genes from broad bacterial repertoire Growth curve biology oMultiplying doubling cells are metabolically active often adapting not all metabolically active cells are multiplying oStress causes adaptation or injury Growth curve biology oStationary phase may represent quiescence or more often growth rate death rate oSome injured cells appear dead viable nonculturable oSome dead cells autolyze Bacteria in broth vs food oBroth planktonic cells oBacteria tend to aggregate attach to surfaces form colonies or biofilms oFoods solid matrix microenvironments oPathogens outnumbered Research vs real food oFood contaminants water air soil raw material feces have mixed microflora oFood ecosystem may select one organism Research vs real food oAt high levels bacteria signal each other chemically consensus oDifferent species interact competitively but sometimes beneficially Research vs real food 0 Programmed successions oGenetic exchanges among strains or species oToxigenic agents including molds grow under conditions that do not permit toxigenesis Major factors interact Temperatures for oTemperature oNutrients Thermophiles 1511 available o 11 Physical oMlnlmum 4045 C W structure OOptimum 5575 C PH spea c OMicroflora oMaximum 6090 C catlons 8 oAntlmlcroblal anlons agents Temperatures for Temperatures for Mesophiles Psychrophiles OMinimum 515 C OMinimum 55 C oOptimum 3045 C oOptimum 1215 C oMaximum 3547 C oMaximum 1520 C Temperatures for or Psychrotrophs 0 kills some cells Mmlmum 395395 C storage preserves oOptimum 2530 C grow slowly in oMaximum 3035 C food cf handout Warm near optimum Danger zonequot depicted OFood spoilage promoted test of sanitation O Danger Zone 460 C 40 140 F or 557 C 41135 F ORapid transition from hot to cold or cold to hot n quotcan zouE r011 mum roons A new Aemmonar nympm 5mm mun E can 015nm Jimmy 512311enfm gwmymw Hot temps gt max for 39 growth cause death OD value time for decimal E 1 reduction at t C organisms 5 us are in log death phase 1n 2quot 3n n 5quot 39 ac Oz value temperature change C to reduce the D value 10 fold 32 w an 64 an 96 112 123 1w F D value example 2 value example m D 5 min 1 ac 15 q a u LOG m quotmm D 5 m 15 2a mmmummc TEMPERATURE 1am Heat Cooking blanching pasteurization not for commercial sterility Cells in log phase are more heatsensitive Heat Heatshock proteins aid adaptation some produced in response to other stresses Mesophiles or psychrotrophs infectious agents must be able to multiply at body Tyndallization boiling on 3 days Day 1 vegetative cells killed spores heatshocked Day 2 veg cells from spores killed last spores heatshocked Day 3 vegetative cells from final spores killed endpoint sterility Eh Aerobic gt0 mV microaerophiles facultative anaerobic lt0 mV Strict aerobes Eh gt 0 mV obligate anaerobes Eh lt 300 mV O Eh Facultative organisms often use available energy more efficiently under aerobic conditions C perfringens may not start growing under aerobic conditions but is not inhibited by oxygen once growth begins Eh Eh hard to measure in foods Live foods metabolize or bind oxygen Packaging modified atmosphere Molds generally strict aerobes Water activity quotaW quot Water available for microbial growth based on water present and on binding by solutes such as salt or sugar equilibrium relative humidity 100 range is 0 to 100 0000000 Approximate aW of some foods Fresh fruit or vegetables 3097 Fresh poultry or fish 3098 Fresh meats 3095 Juices fruit 8 vegetable 097 Cheese most types 3091 Honey 054 075 Cereals 010 020 Minimum aW for some foodborne pathogens Salmonella 093 C botulinum 093 Staphylococcus aureus 085 Most yeasts 088 Most molds 075 range from pH 7 inhibits 8 growth of many acid bot pH 3 46 0000600 pH values of some foods Egg white 7695 Milk 6368 Chicken 5564 Beef 5362 Cheeses most 5061 Tomatoes 3749 Apples 2935 0000 Important minimum pH values for growth of microbes in foods Clostridiam botulinam 4850 Salmonella most types 4550 Staphylococcus aurcus 4047 Yeasts amp molds 1535 pH O Organic acids eg lactic acetic etc more effective antimicrobials than mineral acids oMost effective undissociated at a given pH molar quantity of organic acid gtgt than that of a mineral acid Nutrients available 0C 8 N sources required sometimes growth factors oFoods generally good C 8 N sources oOther factors then nutrients decide which organism predominates Physical structure oBacteria grow on surfaces when they can oSome surfaces melon rind eggshell limit access to nutrients oFood matrix molds often penetrate better than bacteria Physical structure oIf water 8 solutes cannot diffuse freely local variations in Eh 11 and pH are highly possible oHi h viscosity or strongly cel ular structure can eatly limit heat transfer both heating and cooling in foods w Microflora oBacteria in foods variety 8 competition oMicrobial growth may lower Eh 8 pH molds use organic acids as carbon sources 8 raise pH Microflora oBacteria may produce acetic lactic and other acids as fermentation products 0 Some produce bacteriocins proteins that have a highly specific lethal effect on closely related organisms O Competing organisms Staphylococcus aureus Clostridium botulinum O O Programmed succession Milk rapid lactic acid producers lactococci then Slower acid producers lactobacilli that tolerate lower pH39s then Acidstable putrefactive proteolytic bacteria and finally Molds imetabolite tolerancel O lntimicrobials preservatives Materials added specifically to inhibit microbial growth Nitrite for curing meats vs C botulinum Sorbates benzoates 8 other salts of organic acids bacteriostatic not bactericidal lntimicrobials preservatives C02 8 S02 long used in foods S02 is highly toxic to a small segment of the population Spices especially those with strong flavors often viewed as preservatives or disinfectants Probably bacteriostatic at best Antimicrobials radiation UV widely applicable to decontamination of food surfaces food contact surfaces 8 water used in food processing limited penetration Antimicrobials radiation Surface efficiency enhanced by pulsed laser application some pulsed laser applications use visible light Ionizing radiation discussed earlier in course Interactions oThe pH that permits growth of a bacterium near its optimal temperature may be limiting at a less favorable temperature Escherichia coli death rates at 0 pH 5 threepoint moving averages I o 0 o o o I o 39 o 39 o 9 39 39 O 3 I o o 0 o I 0 o 7 075 08 085 09 39095 1 702 water activity Listeria monocytogenes death rates at pH 5 threepoint moving averages water activity Interactions oSafe foods designed combining slightly unfavorable conditions for several parameters to stop target pathogens and spoilage organisms O Interactions This kind of food design has heavy safetg implications modeling iscussed last time is used to make choices then validated by inoculatedpack productabuse trials before a new food product is marketed Applied in HACCP Pathogen Modeling Program PMP httpwwwarserrcgovMFSPATHOGENHTM PHR 250 4907 6p SHIGELLA SPP Dean 0 Cliver Introduction Four species boydz39z39 dysenteriae exneri sonnet serogroups Shigellosis bacillary dysentery Hostadapted to humans primates Characteristics of the disease Infectious dose is 10 100 organisms Incubation period is 12 4 usually 1 3 days up to a week for S dysenteriae l Illness diarrhea with fever and nausea sometimes toxemia vomiting cramps and tenesmus dysentery blood and mucus in stools may cause hemolytic uremic syndrome most severe in infants mild and asymptomatic infections occur Duration 4 7 days shedding up to 4 weeks both shortened by appropriate antibiotics multiple resistance common Characteristics of the organism Nonmotile nonsporeforming gramnegative short rods close genetic relationship to E coli Invades the colonic epithelium many strains produce shigatoxin or shigalike toxin Temperature range for growth straindependent 7 46 C optimum 37 C pH range for growth 5 8 acetic acid stops growth at pH 6 Transmission via food Fourthranked cause of foodborne disease in US 1998 2002 735yr per CDC CAST estimates 90000 163000 cases per year 180 deaths 390 average costcase CDC estimates 90000 cases per year 14 deaths FoodNet 2005 47 cases105 US population z 14000 cases Survives well in neutral pH foods poorly in acid foods may grow e g in watermelon Vehicles may be anything contaminated with infectious human feces water 2 outbreaks in US 1994 baked goods fruits and vegetables chicken hamburger potato salad and finfish have been implicated in outbreaks Isolation and identification Food samples held at 4 C or frozen ifheld gt24 hr Various enrichment broths and selective media are used fairly typical of those for gram negative bacteria Usually lactose negative many other biochemical tests apply Species identification is largely serological Molecular detection typing and subtyping methods are available Treatment and prevention 250C6 2 Treatment with antibiotics is possible but susceptibility testing is advised because multiple resistances are common Prevention is largely based on sanitation Summary Shigella is widespread and potentially deadly shed in human feces Frequent transmission via food indicates frequent sanitation failure Bibliography Council for Agricultural Science and Technology CAST 1994 Foodbome pathogens risks and consequences Task Force Report No 122 CAST Ames IA Gray L D 1995 Escherichia Salmonella Shigella and Yersz39nz39a pp 450 456 In P R Murray E J Baron M A Pfaller F C Tenover and R H Yolken eds Manual of Clinical Microbiology 6th ed American Society for Microbiology Press Washington DC Hajmeer M N and D Y C Fung 2006 Infections with other bacteria pp 341 365 In Riemann H P and D O Cliver eds 2006 Foodbome Infections and Intoxications 3d ed Academic Press Elsevier London Amsterdam Heyman D L ed 2004 Control of Communicable Diseases Manual 18th ed American Public Health Association Washington DC International Commission on Microbiological Specifications for Foods 1996 Shigella pp 281 298 In Microorganisms in Foods 5 Characteristics of Microbial Pathogens Blackie London Lampel K A and A T Maurelli 2001 Shigella Species pp 247 261 In M P Doyle L R Beuchat and T J Montville eds Food Microbiology Fundamentals and Frontiers 2d ed ASM American Society for Microbiology Press Washington DC Lampel K A and A T Maurelli 2002 Shigella pp 69 77 In D O Cliver and H P Riemann eds 2002 Foodbome Diseases 2d ed Academic Press London Mead P S L Slutsker V Dietz L F McCaig J S Bresee C Shapiro P M Griffin and R V Tauxe 1999 Foodrelated illness and death in the United States Emerging Infect Dis 5607 625 Olsen S J L C MacKinnon J S Goulding and L Slutsker 2000 Surveillance for foodbome disease outbreaks United States 1993 1997 Morbid Mortal Weekly Rep Surveill Summ 49SS011 62 PHR 250 4907 6p YERSINIA ENT EROCOLI T ICA Dean 0 Cliver Introduction Genus Y ersim39a was spun off from genus Pasteurella includes Y pestis which causes plague Y enterocolitica is the principal foodborne species and has a reservoir in swine Characteristics of the disease Incubation period usually 3 7 days generally under 10 days Acute febrile diarrhea enterocolitis may mimic acute appendicitis postinfectious arthritis in adolescents and young adults Characteristics of the organism Gramnegative nonsporeforming rods facultatively anaerobic motile by peritrichous agella only at temperatures lt35 C Growth range of temperatures is 2 42 C optimum 28 29 C in raw pork at 7 C has grown to 109 1010 cellsg within 10 days pH range for growth is 42 90 with an optimum of 7 8 Grows in the presence of 5 but not gt7 NaCl Virulence is plasmiddependent and is limited to a few serotypes humans mainly 03 Transmission via food CDC reported 8 foodborne outbreaks 87 cases of yersiniosis during 1998 2002 CAST report estimates 3250 20000 cases of foodborne yersionosis per year in the US with perhaps one death the cost per case is estimated at 5450 CDC estimates 87000 foodborne casesyear 2 deaths FoodNet 2005 36 cases106 US population z 1080 cases Y enterocolitica has been isolated from many foods in addition to pork but the strains found in these other vehicles appear to be avirulent for humans Transmission via water and dairy products has been reported one outbreak was traced to tofu packed in spring water Isolation and identification Samples held at 4 C ifpossible Cold enrichment macerate food in phosphatebuffered saline incubate at 4 C for 2 4 weeks or at 10 C for 3 days or at 15 C for 2 days Enrichment culture sometimes treated with 05 KOH for 15 sec before plating kills many competing organisms Selective media may be inhibitory with 35 37 C incubation use temperatures 32 C PCR detection is also an option 250C6y 2 Treatment and prevention Can be treated with antibiotics other than penicillin and its derivatives Prevention is generally based on thorough cooking of pork and on sanitation including hand washing Summary Foodbome yersiniosis is a highly specialized problem involving transmission from swine It should be preventable by careful handling and cooking of pork and by avoiding cross contamination of other foods however milk anal dairy products have also been vehicles Bibliography Council for Agricultural Science and Technology CAST 1994 Foodbome pathogens risks and consequences Task Force Report No 122 CAST Ames IA Gray LD 1995 Escherichia Salmonella Shigella and Yersinia pp 450 456 In P R Murray E J Baron M A Pfaller F C Tenover and R H Yolken ed Manual of Clinical Microbiology 6th ed American Society for Microbiology Press Washington DC Heyman D L ed 2004 Control of Communicable Diseases Manual 18th ed American Public Health Association Washington DC International Commission on Microbiological Speci cations for Foods 1996 Y ersinia enterocolitica pp 458 478 In Microorganisms in Foods 5 Characteristics of Microbial Pathogens Blackie London Kapperud G 2002 Yersinia enterocolitica pp 113 118 In D O Cliver and H P Riemann eds 2002 Foodbome Diseases 2d ed Academic Press London Mead P S L Slutsker V Dietz L F McCaig J S Bresee C Shapiro P M Griffin and R V Tauxe 1999 Foodrelated illness and death in the United States Emerging Infect Dis 5607 625 Nesbakken T 2006 Yersinia infections pp 289 312 In Riemann H P and D O Cliver eds 2006 Foodbome Infections and Intoxications 3d ed Academic Press Elsevier London Amsterdam Olsen S J L C MacKinnon J S Goulding and L Slutsker 2000 Surveillance for foodbome disease outbreaks United States 1993 1997 Morbid Mortal Weekly Rep Surveill Summ 49SS011 62 RobinsBrowne R M 2001 Yersinia enterocolitica pp 215 245 In M P Doyle L R Beuchat and T J Montville ed Food Microbiology Fundamentals and Frontiers 2d ed ASM American Society for Microbiology Press Washington DC Microbiological Testing of MEhidadTalkaiimi WM PhD VMPHRZSU uc Davis Bacterial pathogens E collO157H7 Salmonella L monocyfogenes S aureus MEhidadTaIkaiimi WM PhD VMPHRZSU uc Davis Toxins and microbial metabolites Bacillus cereus enterotoxin Clostrldlum perfrlngens toxin E collO157H7 enterotoxin I I Staphylococcal enterotoxin Aflatoxins and Fumonisin MEhidadTalkaiimi WM PhD VMPHRZSU uc Davis Importance of detecting microorganisms in food Investigating outbreaks of foodborne disease Assessing the safety of the product to consumers Assessing the stability or shelf life of the product under 39 s normal storage condition 0 Determining the level ofsanitation during product preparation Regulatory compliance 0 Incidence surveys for pathogens MEhidadTalkaiimi WM PhD VMPHRZSU uc Davis Indicator or spoilage microorganisms Aerobicanaerobic plate counts Coliforms E coll yeast amp mold counts Psychrotrophs MEhidadTalkaiimi WM PhD vmwman uc Davis Bacteriological detection methods Direct enumeration Microscopic count Colony Forming Unit CFU count Nonselective media Nonselective differential media Selective media Selective differential media MEhidadTalkaiimi WM PhD vmwman uc Davis Bacteriological detection methods Indirect Determination Most Probable Number Method MPN Enumeration of Injured Cells by Selective Media Overlay Method Thin Agar Layer Method MEhIdadTalkaIlml WM PhD VMPHRZSU uc Davis Bacteriological detection methods Pathogen Isolation Sample does or does not contain microorganism of interest Preenrichment step Selective enrichment step Testing on medium containing selective andor differential agents MEhIdadTalkaIlml WM PhD VMPHRZSU uc Davis Testing for bacterial toxins Agglutination Radioimmunoassay RIA Enzyme Linked Immunosorbent assay ELISA Enzyme Linked Fluorescent Inmmunoassay ELFA MEhIdadTalkaIlml WM PhD VMPHRZSU uc Davis Regulatory compliance testing USDAFSlS quotMegaReg Testing Meat and poultry slaughter plant and raw ground products processing facilities are required to test for generic E coll an Salmonella underthe provisions of the HACCP program or Pathogen Reduction Final Rule Quantitative testing for generic E coll Qualitative testing for Salmonella MEhIdadTalkaIlml WM PhD VMPHRZSU uc Davis Regulatory compliance testing 0 FDA Seafood or other food products 0 Examples include microbial analysis for spoilage microorganisms or pathogens in seafood or cheese State Dairy Testing Pasteurized Milk Ordinance PMO These tests relate to the quality of various dairy products Microbial testing and analysis include coliform counts standard plate counts SPC MEhIdadTalkaIlml WM PhD VMPHRZSU uc Davis Testing considerations Selection of sampling techniques Selection of sampling kits Use of AOACapproved methods MEhIdadTalkaIlml WM PhD VMPHRZSU uc Davis Testing methods 0 Standard Methods for the Examination of Dairy Products 0 Standard Methods for the Examination of Water and Wastewater Standard Methods for the Examination of Seawater and Shell sh o Compendium of Methods for the Microbiological Examination 0 Food Bacteriological Analytical Manual of Food and Drug Administration MehldadTalkallml WM PhD VMPHRZSU uc Davis ISO 17025 0 General Requirements for the Competence ofTesting and Calibration Laboratories For international benchmark for approving the competence of the testing and calibration 0 ISO 17025 allows laboratories to carry out procedures in their own ways but an auditor may require the laboratory to justify using a particular method ISOIEC 17025 is divided into two principal parts Mana ement requirements 0 Technical requirements MehldadTalkallml WM PhD VMPHRZSU uc Davis ISO 17025 Management requirements include paragraphs on anization a Complaints quot399 o Controlofnon Duality sys conformity testing Document control Corrective action Preventive action anagem ent r o o 0 Records 0 Internal audits o eviews 0 Technical Requirements o 11 z II 2 o oio Ill 0 E n 0 Ill 0 Service to the client MehldadTalkallml WM PhD VMPHRZSU uc Davis ISO 17025 Technical requirements include paragraphs with much detail on o General 0 Equi ment Femquot o Measurementtrace ability o Accommodation and environmentalconditions Sampl39w o Testandcalibration o Handling andtransportation oftest methods including and calibration items samp This includes requirememso Assuring the quality of test and on ts for method validati calibration resul laboratory developed quotommndardixed39 o Assuring the quality of test and standardized butused callbmtlon resul 5 outside of their intended range and measurement uncertainty MehldadTalkallml WM PhD VMPHRZSU uc Davis Microbiological uncertainty o It means a method used to estimate the uncertainty associated with model inputs assumptions and stru ctureform 0 Many microbiological laboratories have h d procedures available for monitoring variability in duplicate results generated by laboratory analysts for e ime 0 Studies and more complex statistical calculations MehldadTalkallml WM PhD VMPHRZSU uc Davis 0 Usually qualitative testing at the limit of sensitivity 0 Subjectivity problems Viruses and parasites 7 how are the different cells rare exception with lar l39a 0 Cannot multiply in food no toxins or other metabolites 7 either remains infectious or not 0 Cannot be enriched for testing 0 Cannot multiply otherthan in specifc living host G d MehldadTalkallml WM PhD VMPHRZSU uc Davis Sensitivity concentration method detection method 0 Concentration start with servingsize sample offood r water7 Drinking water samples o en 107100 liters Solid food samples can39t be concentrated 7 separate agent from food solids into liquid ase 0 Virus 30 nm concentration adsorptionelution precipitation or brute force Concentrating protozoan cystsoocysts 4720 pm largerthan bacteria ltration centri Jgation to hion bottom 0 tu e or onto cus o lmmunomagnetic ca ture M n 2 YdadTalkavlml WM PhD VMPHRZSU uc Davis Detection O Vlruses susceptible hosts Ul l molecular methods used o Mostvlruses RNA onlv7 reverse transcription RT requlred forPCR o Botn RT and RCR are very susceptible to intenerence bv substances in environrnental samples realtirne RCR and nucleic acid sequence based ampllflcatlol l NASBA o PCR productanalvsis gelelectrophoreslsbloserlsorsverlflcatlorl sequencing Rrotozoa larger tnan bacteria so microscopy is an option Stall lll lg uorescent orotneiWise lmmunofluorescerlttechrllques RCR multlple cnrornosornes MehvdadTalkavlml WM PhD VMPHRZSU uc Davis Specificity absence of false positives o Detecting only the target organism o What ifa broadspectrum test is wanted7 0 Detection of noninfectious inactivated agent false positive 0 False positives from noninfectious viruses 7 look for alternations in the virus that o Accompanyinactivation RNase sensitivity 0 False positives from noninfectious protozoa 7 excystation PCR for Cryptosporidium in vitro culture of Giardia MehvdadTalkavlml WM PhD VMPHRZSU uc Davis Overview Methods for 39 39 39 testing of foods are limited by sampling 7 spoilage Organisms and some indicators may be fairly omogeneously distributed but pathogens are typically spotty in distribution and present at relatively low levels Because of distribution and sampling problems sensitivity false negatives and specificity false positives present continuing challenges MehvdadTalkavlml WM PhD VMPHRZSU uc Davis Overview o The key to detection of bacterial pathogens is usually enrichment which is not an option with viruses and protozoa detection and enumeration media may be selective differential both or ne39t er 0 Bacterial toxins are usually detected by some adaptation of serology 0 With viruses and protozoa sample processing and concentration as well as a sensitive nal detection method are necessary to a satisfactory outcome and problems offalse positives with noninfectious contaminants rema n MehvdadTalkavlml WM PhD VMPHRZSU uc Davis Thank you MehvdadTalkavlml WM PhD VMPHRZSU uc Davis PHR 250 Foodborne Infections and Intoxications Course Leader Dean 0 Cliver Hans P Riemann 1920 2007 CLASSIFICATION OF FOODBORNE PATHOGENS SOURCES OF CONTAMINATION Dean 0 Cliver Outline 1 Taxonomic classi cation 2 Classi cation by mode of pathogenesis 3 Overview of how pathogens enter foods Taxonomic classi cation of foodborne pathogens OPrions Algae Viruses cyanobacteria Bacteria OMetazoan parasites Fungi oToxic plants and OProtozoa anlmals Infectious agents Properties of foodborne infections OAgent must be present in food in Viable infectious form at the time of ingestion OAgent multiplies to cause illness incubation period Infectious agents oPrions new variant CID oViruses hepatitis A noroviruses etc OBacteria Campylobacter Clostiidium per ingens Escherichia coli Listeria Salmonella Shigella Vibrio etc Infectious agents oProtozoa Cryptosporidium parvum Entamoeba histolytica Giardia lamblia Toxoplasma gondii etc oMetazoan parasites roundworms tapeworms ukes Intoxicating agents Properties of foodbome intoxications OTOXic substance is present in food at the time of ingestion OOnset of illness is often more rapid Intoxicating agents oBacteria Bacillas cereas Clostridium botulinum Staphylococcus aureus Algae cyanobacteria Intoxicating agents OFungi Aspergillus F usarium Penicilliam etc OTOXic plants and animals mushrooms cassava fugu etc OChemicals Other classes of foodborne disease quotExceptionalquot foodborne diseases OAllergy serologic reaction Olntolerance enzyme deficiency abnormal people Other classes of foodborne disease Idiopathic illnesses OAcute quot Chinese restaurant syndrome OChronic c ancer heart disease quotFood Chainquot m Retailer Distributor Consumer Processor Food Service Sources of foodborne pathogens Preharvest Olnherent toxicants acorns cassava olives etc Sources of foodborne pathogens Preharvest OZoonoses enterohernorrhagic E coli Trickinella spiralis Brucella Coxiella burnetii Mycobacterium bovis prions of BSE etc Sources of foodborne pathogens Preharvest oField contaminants Cryptosporidium parvum enterohernorrhagic E coli Vibrio parahaemolyticus etc Sources of foodborne pathogens Harvest or slaughter OCrosscontarnination Listeria Salmonella OWater enterohernorrhagic E coli hepatitis A virus etc OHumans hepatitis A virus Salmonella etc quotFood Chainquot Sources of foodborne pathogens Processing OProblems rare in US at present OColonization of facilities by Listeria Salmonella Olf bakeries are included Viruses Grower Retailer Inputs Distributor Consumer Erma Food Service quotFood Chainquot Grower Retailer Inputs Consumer 39 Sources of foodborne pathogens OStorage and distribution most problems with temperature control rather than contamination Processor Food Service quotFood Chainquot I nputs Distributor Consumer Sources of foodborne pathogens Retailing and food service oOpportunities for human source contamination hepatitis A Virus Shigella pathogenic E coli other than EHEC oCross contamination with EHEC Listeria Salmonella etc quotFood Chainquot Grower Retailer quotquotW Distributor memma Processor Food Service Sources of foodborne pathogens Final preparation and serving OOpportunities for human source contamination bacteria amp Viruses Giardia lamblia Taem39a solium etc Summ ary oFoodborne pathogens can be classified taxonomically or by mode of pathogenesis oPathogens may enter food at any stage some risks are more easily remedied than others PROTOZOA life cycles Protozoa Transmitted Trophozoites merozoites tachyzoites 7 active feeding Vla FOOd and water dividing bradyzoites C sts 7 inert transmission form PHR 250 y exception T oxoplasma Gamonts gt zygote gt oocyst sporozoites Giardia lamblia duodenalis intestinalis Leading protozoan cause of foodborne and waterborne disease in US CDC 98i 02 3 foodborne outbreaks 119 cases 037 04 2 waterborne outbreaks 14 cases Spheroid cysts 9712 um long Giardia cyst Glardla f A s mienbv Stage A magnum aw Giardia trophozoite Giardia lamblia lncubation 7710 days characteristic diarrhea from noninvasive colonization of upper small intestine may persist for weeks if untreated asymptomatic infections very common Reservoirs humans beavers cattle and other animals Giardia lamblia vehicles Unfiltered surface water Giardia is fairly resistant to chlorine Drinking water recontaminated with sewa e Fruits vegetables salads and other foods subject to direct or indirect fecal contamination Cryptosporidium parvum Oocysts from humans cattle other domestic amp wild species humanspecific species C haminis Small 476 um tough chlorine resistant Ctyptosporidium parvum Largest outbreak of waterborne disease in history Milwaukee 1993 ca 403000 cases but only one waterborne US outbreak during 037 04 Cryptosporidium parvum Outbreaks from apple juice cider 1993 amp 1996 and raw milk and a few other food vehicles CDC 987702 4 outreaks 130 cas s e FoodNet 2005 N8850 cases C parvum C hominis Incubation l week profuse diarrhea usually lt30 days shedding 2 months intracellular parasitism treatment is rehydration Cryptosporidium 91 quot hominis ommw m C parvum oocyst C parvum excysting C hominis 12s CryptosporzM rM1l w e V I C parvum sporozoites C parvum or C hominis Cryptosporidiosis is diagnostic of AIDS in HIVpositive persons amp will generally persist with intermittent symptoms for life C parvum or C hominis Concem for cryptosporidiosis especially waterborne is evoking stringent measures in the Us and will have a significant impact on agriculture involving ruminants Entamwba histolytica Once a frequent cause of waterborne disease in the US now fairly rare here Continues to be a very significant threat in the poorer countries Entamwba histolytica Causes amebic dysentery sometimes abscesses of liver or other organs trophozoites are invasive Humanspecific transmitted via fecally contaminated water or food A Dwgnashnsiaae o H mm in em A A man cummun i mngba histolytica 0 o Ymuma4e5A 3 x x 39 t 3 mmquot 1 r v is quot3A ampn OM sA A A 5mm b V A Entamwbu histolytica Entamwba histolytica T oxoplasma gondii Outbreaks acute foodborne rare CAST 2090 cases 42 deaths 26 billionyr XI2 from congenital blindness hydrocephalus retardation T gondii life cycle T oxoplasma gondii Cats are de nitive hosts usually infected by eating infected birds or rodents odcysts not immediately infective in cat feces for up to 3 weeks contaminate animal feed garden vegetables other foods water em T gondu oocyst 2 e W 031553 V g of M armsxeaszgzxnzmzxam myzoiles lacahze m neural 2 E asaiazztmd Z we ems via me bloodsheam S 0 0 e E A sip T gondii tissue cyst T oxoplasma gondii quot i I Tissue cysts bag of bradyzoites in pork mutton beef killed by cooking or irradiation freezing does not eliminate them completely Toxoplasma gondii Tachyzoites may encyst in various tissues often CNS in humans cellular immune response causes encystation as bradyzoites tissue cysts well tolerated in humans but may be reactivated if immunity is later impaired Cyclospora cayetanensis Human speci c delayed maturation days to weeks under favorable conditions of oocysts in feces makes person toperson transmission unlikely Fairly common in parts of Latin America and Asia Cyclospora cayetanensis Rare in US but caused an extensive nationwide Canada outbreak in May June of 1996 eventually attributed to raspberries imported from Guatemala again in 1997 embargoed in US but not Canada in 1998 back in 1999 Cyclospora cayetanensis CDC 98 02 9 outbreaks 325 cases FoodNet 2005 450 cases 01k Sii f f d a ufectiva Stage oocysts in ywl 9m cayeta szs Unsporulated Sexual Asexual 9 a era 9 v G I Excysealann oczeu1 e zygote Memo Memnt ll l Cyclospora cayetanensis Presently there are just four Guatemalan farms that may be permitted to export raspberries to the US contingent on fecal testing of the farm workers No positive fecal tests had resulted at last report Summary Limited look at foodbome protozoa Five agents discussed three species Cryptosporidium hominis Cyclospora cayetanensis amp Entamceba histolytica are humanspeci c amp transmitted by a fecaloral route Summary Others all transmitted zoonotically at least some of the time either Via infected animal feces or tissue Human feces also important sources of Cryptosporidium hominis amp parvum oocysts and Giardia lamblia cysts that may be transmitted to humans Via water or food VIRUSES amp PRIONS TRAN SMITTED VIA FOOD AND WATER Dean 0 Cliver Human enteric Viruses 0 Specific for humans Olnfect perorally shed in feces Classification size nucleic acid type appearance Replication inside a host cell Food and waterborne Viruses Enteric virus groups Size NA RNA DNA nm strands Causes of foodborne outbreaks US 98 02 25735 single astro parvo calici picorna 70785 double reo adeno rota Rank Agent Cases 1 Norovirus 27121 212 2 Salmonella 16821 131 3 C perfringens 6274 52 4 Escherichia coli 4864 30 5 Shigella 3677 29 Causes of foodborne outbreaks US 98 02 Rank Agent Cases 6 Staph aureus 2766 22 7 Campylobacter 1440 11 8 Hepatitis A Virus 981 08 9 V parahaemolyticus 613 05 10 Bacilluscereus 571 04 1EID estimates 1999 Icosahedral symmetry RNA Virus re lication Virus cytoplasm cell membr ane RNA virus replication 6 O coat proteins RNA Virus replication 7 coat proteins RNA virus replication 8 Noroviruses CDC 27171 illnesses 1 death Oest 92 million foodborneyr CAST 181000 casesyear 0 deaths 890 0US 98 02 657 outbreaks History and naming Norwalk Ohio gastroenteritis outbreak 1972 Small round structured Viruses SRSV Norwalklike Calicivirus group small 30 nm singlestranded RNA protein coat has dimples The disease Virus from ill or convalescent person Via feces or vomitus Colonization of intestines incubation 1 2 days The disease 92 Severe diarrhea amp vomiting 12 60 hr usually 24 48 hr virus shedding up to 7 days Antibody is not protective TransmissionControl Routes persontoperson or 0via water undercooked shellfish cf HA 0food handled by an infected person Prevention sanitation cooking 3 Diagnosis of noroviral gastroenteritis Clinical vomiting amp diarrhea 318 hr incubation Virus in feces 0Tests for particles or antigen 0Tests for viral genome Antibody production serogroups 3 Estimated annual hepatitis A CDC Nll000 cases 39 CAST 04800735900 cases 014 deaths 5030case Hepatitis A virus Picornavirus Oca 28 nm diameter Osingle strand RNA 0coat protein comprises 60 copies of each of four structural polypeptides Relatively resistant to heat and to n History Viral hepatitis recognized ca time ofWorld War II Fecaloral transmission of infectious hepatitis now hepatitis A recognized much later History 2 576 hepatitis viruses now known Only hepatitis A is known to be transmitted via food and water in North America The disease Virus in feces of infected person Entry via intestines Liver colonized Olnfected cells destroyed by host 39 e s onse Olncubation 1550 days average 28730 The disease 2 Virus shed in feces 172 weeks before onset TransmissionControl Routes 7 persontoperson or via water drinking irrigation Illness fever malaise anorexia under JOOkedi Shell Shy 0f fOOd nausea abdominal discomfort7 handled by an mfeaed Person jaundice Prevention 7 sanitation cooking Usually complete recovery after a W U39S397 1995 few weeks permanent immunity Food as a vehicle 7 5 Evenm In Hepatitis A Virus Infection cnncmuness Other gastroenteritis Viruses Astroviluses 7 occasionally Infection ALT foodborne some rephcate 1n cell e 0 Rotaviluses 7 more often infant d1a1rhea than foodborne d1sease Adenoviluses 7 serotypes 40 amp 41 not known to be foodborne Coronaviruses 7 questionable cause of human diarrhea foodborne once Response gt Rotaviruses I Adenoviruses Coronaviruses 11 kw Other Viruses and food 0 Human enteroviruses olioviruses coxsackieViruses echoviruses 7 rare in US Hepatitis E Virus 7 water food 0 Tickbome encephalitis Virus 7 Detection amp monitoring 0 Diagnosis adapted Cell culture 0Cytopathic effects milk amp milk products Slovakia OPlaques Nonproblems 7 hepatitis B C amp D herpes HIV hantaVirus Poliovirus in Viru plaques fection CPE Detection of viruses in food Sample processing Oliquefaction 0 clarification 0 concentration Test methods Oprobes ORT PCR 0 antigen capture RTPCR of hepatitis A Indicators Bacteria fecal coliforms Escherichia coli etc Viruses vaccine polioviruses Phages fecal origin resemble human Viruses Preventing transmission 39 Food vehicle Wager vehicle Shellfish as vehicles Filter feeders v v I z gzssza N Other food vehicles Prevention Sanitation handwashing Cooking amp other means of inactivation 3Viruses are inert can t multiply in food EPersist or lose infectivity inactlvatlon Cooking inactivates viruses saga ag it Freezing preserves viruses ZUV inactivates viruses on surfaces or in water Some viruses are inactivated by drying EChlorine inactivates viruses on surfaces or in water Now for something completely different PRIONS ETransmissible spongiform encephalopathies T SEs Accumulation of abnormal prions in brain leads to spongiforrn degeneration All are fatal Some are contagious Prions are Low MW peptides found in CNS amp some other organs Normal folding depends on amino acid sequence normal 0 abnormal A prion Prion PrPC PrPs Normal human prion protein fl7ms7m1f 3 r m Normal human prion folding Abnormal prion folding El Normal PrP cycle PrPSc in neuron is 1 0 QM f S 5wm SM 6 Extracellular PrPSc Prp aggregates sumx Assocmza Wm M Li W Old TSES Scrapie in sheep CreutzfeldtJakob disease CJD sporadic etc in humans Transmissible mink encephalopathy Chronic wasting disease deer elk New TSES Bovine spongiform encephalopathy BSE 7 mad cow disease Feline spongiform encephalopathy New variant CID vCJD in humans Prion infection bovine contact re mn gum on N normal 0 bovine abnormal BSE in cattle UK April 1985 to December 2004 184131 confirmed cases ofBSE 375yr incubation Control by not feeding rendered bovine meatandbone meal MBM to cattle 7 slow enforcement BSE in cattle UK 2 Slaughter of affected m Enormous research effort No BSE prions found in red meat voluntary muscle or milk Vertical transmission unlikely Carcass disposal precautions BSE in cattle elsewhere Some cattle much beef and a lot ofMBM exported from UK to other countries ow ca 30 countries have BSE few thousand cases all in Europe except Japan Isiael Canada amp US so far i L I YAI MJYA Nonatransmission by prion 5 12 cnnmct nquot Ehng scrapie i E ahnnnnai normal 0 a human UK 7 VCJD gt10 incubation Interaspecies transmission Ca 1994 TSE in cats UK including zoo species In 1995 NCJD in yo ung people 393 is in more than age VCJ39D d e distribution of victims Prion crossainfectjon ha mm recnnriguiau39nn vine ahnmuai A A nmuai a A human 0 ahnmuai nnnuai canine Nonatransmission by prion mm no change A A 9amp0 Impact of VCJD l65 people in UK 37 in the rest of the world affected by 0407 Even in UK ltCJD rate 28 vs 48 in peak year 200039 5 vs 57 2006 Far less than deaths from other foodborne diseases HUGE reaction Sporadic CJD amp VCJD in the UK 1990 2006 Wnum 199m 992 994 1995 1995 2mm 2mm 2mm 2mm 2mm Impact of VCJD 2 Specified bovine offals banned most BSE countries Cattle gt30 months old not eaten in UK carcasses incinerated no longer Slaughter cattle gt30 24 months old tested other BSE countries Impact of VCJD 3 Genetic susceptibility all primary VCJD patients tested have been homozygous for methionine at codon 129 of their prion gene 40 of population Restrictions on blood donation and use 3 probable UK cases US measures No mammalian lVlBM can be fed to foodsource ruminants Restrictions on blood donation Scrutiny of biologicals Slaughter of downer cattle prohibited US measures 2 No risk materials in human food supply from animals gt30 months old Other prohibitions pending More testing of downers dead onfarm suspects at slaughter C c 39 Dorsal Horn Dorsal Root Dorsal WW root ganglion sum Cord N0139mal human brain HampE vCJD HampE stain u N V 1 n z u a a p u a M u 1 u INOI39mal human brain IHC BALANCED RESPONSE ESE mmm 3 Drama in North America chronic wasting disease Deer amp elk Colorado Wyoming Other states Canadian provinces Environmental transmission feces Transmissible to humans Processing carcasses 7 food safety Now upstaged by BSE Summary Human enteric viruses fecal contamination Cooking or other means of inactivation depur ation Detection vs indicator systems for monitoring Summary 2 Prion diseases are here in North America Threat to human health is minimal Measures being imposed may well lessen overall food safety INCIDENCE OF FOODBORNE DISEASES Dean 0 Cliver W help from Michele Jay Russell Disease foodborne Criteria Food attribution oAgent from patients found in food ngerprinting OFOOd consumption matches among patients Disease foodborne Other criteria O Fingerprints match among patients oFrequently foodbome disease oGastrointestinal symptoms How do we know a disease is foodborne OOutbreaks VS sporadic cases recognition of common source outbreaks OAcute VS chronic illnesses acute VS chronic exposures PulseNet 9A national network of public health laboratories that perform DNA fingerprinting on bacteria that may be foodbome PulseNet c0nt OPermits rapid comparison of these quotfingerprintquot patterns through an electronic database at the CDC PFGE of Maldigested genomic DNA of PulseNet cont E coli 0 H1 outbreak stra39 quot PulseNet oAllows identi cation of concurrent outbreaks across wide geographical areas and aids identi cation of common source outbreaks Atrisk populations Atrisk populations 1990 CAST 1990 CAST Cate o Peo 1e x 106 Cate o Peo 1e x 106 Pregnant women 5657 QIn nursing homes 1553 Neonates 4002 oCancer nonhospitalized 2411 oElderly gt65 29400 Organ transplant 0391 QAIDS patients 0135 How are foodborne Reporting Channels illnesses reported from p ysmlan 0r 7 Repom39ng channels oLevels of government priorities oComPila on oPaper vs electronlc Re Om39n oFoodNet 7 data from diagnostic P g laboratories oOutbreak suspected investigated Compilation OStructure of information gathering OStructure of information recording Reporting OChoice of quotmedium OTiming FIGURE 1 Number of reporled loodborne disease oulbreaks 1993 2002 1500 u Pavevlumis m I Wenmsm LaFORS39 WU ma mm was was mm um mm 2000 2am 2am 2mquot a snwunm Number 5 Veer 39E ecnomc Foodborne Outbreak Heponmg System U S statistics on foodborne disease OOutbreaks only OReported incidence outbreaks cases deaths OquotCausesquot etiology contributing factors US statistics on foodborne disease OSeasonality place food was eaten vehicles identity vs newquot OUndetermined etiology i FoodNet OEstimates from CDC in Emerging Infectious Diseases Foodborne diseases active surveillance network OCampylobacter E coli 0157 STEC non0157 Listeria Salmonella Shigella Vibrio Yersinia Cryptosporidium Cyclospora HUS OAll clinical labs contacted at least monthly FoodNet oCollaborative effort between state health departments USDA FDA CDC OPrincipal foodborne diseases component of CDC s Emerging Infections Program EIP oEstablished in 1995 in four sites OCurrently 10 EIP sites with 41 million persons under surveillance CA EIP site includes San Francisco Alameda and Contra Costa counties FOODBORNE DISEASE OUTBREAKS US 199872002 2 Outbreaks Cases Deaths No No Bacterial 1184 178 37887 295 7 o FOODBORNE DISEASE OUTBREAKS US 199872002 Outbreaks Deaths No No No Con rmed 2167 326 68991 537 76 Chemical 221 33 1140 09 0 u e 00 P fasmc 23 03 530 05 0 UndeteImined 4480 m 59389 g V1Ia1 709 107 28274 220 0 etiology Multiple 30 05 1050 08 0 Tota15yr 5547 100128380 100 88 Cor nned 2157 325 58991 537 75 BACTERIAL FOODBORNE DISEASE REPORTED VS EST 2 Species Reported Estimated 199872002 annual Campylobacter 1440 1963141 C105 per 39ingem 6724 248520 Escherichia 005 4864 173107 L monocytogenes 256 2493 Sabnonella 16821 1341873 FoodNet data Organism 199amp 2005 199 Cmnpylobacter105 217 127 E 501139 0157 105 23 11 Linena 106 49 30 Salmonella 105 135 145 Shigella 105 77 47 ANNUAL FOODBORNE PARASlTlC amp VIRAL FBN CASES US BY SOURCE DISEASE REPORTED VS EST Agent Passive Estimated FoodNet Species Reponedy Estimated 19987 Meadet 2005 199872002 annual 2002 al39vlggg 3X10 Glardza 119 200000 Tumplasma 0 112500 Campylubacter 1440 1960000 38100 Trzchmzlla 33 52 Salmonella 16821 1340000 43800 HepatitisA 981 47170 Noroviruses 27171 9200000 California FoodNet data annual Agriculture Orga iSm 1996 2005 39Leads US 8800 gen1059mm 1998 Cryptuspmzdmm 268 295 Cycluspma 16 15 Vzbnu 24 27 ersmza 89 36 Foodborne outbreaks in Foodborne illness in California 0 9 million illnesses viralgtbacte1iagtparasitic 0 39000 hospitalizations bacterialgtviralgtpa1asitic O 600 deaths bacterialgtparasiticgtviral Con mied etiologic agents CA Etiology 1999 2000 2001 2002 Bacterial 35 95 27 60 21 54 20 48 Parasitic 1 3 1 2 3 8 0 0 Chemical 0 0 2 4 4 10 4 10 Viral 1 3 15 33 12 31 18 43 T0121 37 100 45 100 39 100 43 100 Foodbome outbreaks California Year Outbreaks Increase Con rmed Suspected Cases 1999 121 3325 20 3731 55 46 2000 141 3716 17 45 32 71 50 2001 1772806 25 3922 103 58 2002 207 3355 17 40 20 143 69 Speci c agents in Food vehicle by year of outbreak CA foodbome outbreaks CA Etiology 1999 2000 2001 2002 Norovirus 13 1431 1231 1845 SI 11 603139 924 1329 513 820 Salmonella Ente dis 1438 617 13 13 EcoliOlS7 25 13 513 513 Shigella 514 39 718 25 Vehicle 199171995 199672000 Produce l 2 29 30 Meats 17 30 14 15 Dairy 3 5 2 2 Eggs 12 21 17 18 Seafood 4 7 7 7 Multiple 7 13 16 17 Other 12 21 1111 Includes only outbreaks with a con rmed etiologic agent What about foodborne disease in other countries eg Europe oSome have no reporting mechanism OSalmonella is ahnost everywhere may be presumed foodbome oCampylobacter often not sought Other countries OViruses rarely reported hepatitis A presumed foodborne in Germany O Undetermined etiology vs otherandunknown and infectious enteritis oUK s special problem VCJD CJD in the UK Year Sporadic vCJD Other 2001 58 20 9 2002 72 17 5 2003 76 18 11 2004 51 9 6 2005 65 5 13 2006 57 5 10 Other countries OSome countries seem not to consider foodborne disease from food prepared and eaten at home whereas others take this very seriously OCanada similar to US except that foodborne virus disease is rare and acute illness is sometimes attributed to yeasts and molds Other countries OEuropean Union now has a program Australia and New Zealand seem to be on the way OPan American Health Organization L atin America amp Caribbean What might we aspire to OMore timely reporting OMore complete reporting OMeasures of severity and economic impact M0netary costs Human costs OFoodNet Prognosis for foodborne disease reporting oFrom physicians to national health services incentives to report are lacking oFoodNet oUndetected problems don t require solutions disincentives oWho speaks for the public Summary Olnformation on incidence of foodborne disease quoteducatedquot 2 guesses OThis ignorance has led to misapplication of limited resources for food safety Clostridium perfrin gens Dean 0 Cliver materials from M N Hajmeer Clostridium perfringens H Outline 0 Historical background 0 C perfringens characteristics 0 Foodborne disease estimates 0 Classi cation 0 Pathogen prevalences 0 Clinical features amp mechanism of disease C perfringens enterotoXins and spores Immunity reservoirs shedding growthsurvival and detection Background 0 18905 FW Andrewes and E Klein were involved in linking Clostridium welchii now C perfringens with food poisoning 0 They associated eating foods contaminated with C perfringens with several foodborne outbreaks Outbreaks were characterized with mild to severe diarrhea and abdominal pain Background 0 1892 The microorganism was found in a variety of diseases gt gas gangrene gtappendicitis gtpuerperal fever infection of the placental site following delivery or abortion gt enteritis B ack ground 0 1939 to 1946 Several outbreaks observed gtIn the UK during WWII gtShortage of meat led to the practice of cooking meat for later consumption Background I 1939 to 1946 Several outbreaks ed gtFirstwa1ning offood poisoning came from Knox and Macdonald 1943 gtVehicle gravy made the previous day Was heavily contaminated Wi anaerobic sporing bacilli including C perfringem gtChildren became ill a er eating contaminated meal Background I 1939 to 1946 Several outbreaks observed gtIn the US the rst proven outbreak of C per ingem Was described by McClung 1945 gtExamined 4 foodborne outbreaks associated With eating c 39cken steamed 24 hrs before consumption Background I 1948 Severe necrotic gastroenteritis occurred in Germany gtThe vehicle for the illness Was home canned ra bit gtThe associated strain Was C per ingem type C Background I 1953 Hobbs and associates showed that eating food contaminate With C perfringem could lead to diarrheal food poisoning I Pioneered Work establishing C per ingem as a cause of food poisoning Background I 1954 Experiments Were conducted in US With human volunteers Dac gtThe strain fed Was English strain ofC perfringem gtVolunteers failed to develop any symptoms ofdisease I Public health signi cance Was not fully accepted in US until the 1960s Background I By the 1960s and 70s enough information had accumulated to indicate that C perfringem foodborne poisoning is caused by the release ofthe toxin during sporulation of the microorganism in the intestine of infected individuals Who ate food heavily contaminated With C perfringem Best estimates of annual cases and deaths for foodborne diseases USA Cases Peri Per cent 0 CDC 199872002 130 outbreaks 6724 cases 4 deaths Characteristics of C pelfringens Gram positive nonrnotile encapsulated rods With square en Anaerobe but more oxygentolerant than C botulinum Produces acetone butanol ethanol butyric acid acetic acid propionic acid lactic acid carbon dioxide and hydrogen I Ferments sugars starch and pectin 1 w 0 39 I1 5 u l P s quot l l 1 Spores and Sporulation Because it is a sporeformer the pathogen can survive in the environment Spores are seldom formed in food Sporulation requires a wellbuffered medium rich in nutrients Spores are form ed in the intestinal tract spores shed in feces Classi cation of C perfringens is Based on Toxins Produced T Type Classi cation of C pelfringens is Based on Toxins Produced The alpha toxin is a phospholipase the others are hemolysins or cause necrosis The different types cause a variety of diseases in animals some of them very severe Classification of C perfn39ngenxis a on Toxins Produced Type A is hemolytic o and p and non hemolytic Killing 90 ofspores takes 5 a 17 minutes at 100 C for no hemolytic suaahs andless than one minute for betahemolytic suaahs C peifringenx Prevalence in Foods Incubation time to illness is in Duration ofillness is 1224 in Clinical Features of C peifringenx Clinical Features of C peifn39ngens S V dquot quoth quot y i Large numbers ofthe pathogen can he fever shivering headaehe found in fem and food abdominal pain dehydration Signi cant amount ofenterotoxin also found in feces Infective dose is high Abou 8 vegetative ee11s need to he ingested to cause symptoms Mechanism of Disease c perfrmgens produces toxin mediated infection known as perfrmgens enteritis c perfrmgens produces food poisoning without colonization 4 Symptoms a Mechanism of Disease c perfrmgens in food 2 Ingestedcellsbeginto sporulate a er passing o e 3 Enterotoxinproduced in sman intestine during sporulation Mechanism of Disease Spwrulaum is peerih mostfoods ihererere eehiain iime or he mtamwxm Spwrulaum is rapid in smau inlesunes enlamoxin found in 1042 h hanism or Disease eat shock 70 e100 c boosts geimihaiien and yields crememe 1r food such as mam emiaihihg spores is heated and Ian for some ume at gwwih hemp erauxe me nmedquot produ epien Dfspwres and enieremxih in me small incesiihes Mechanism of Disease Avoid prebiems by beiiihg food immediaieiy b efore eating to and gtPreva1t spwrulahm in me incesiihes Mechanism of Disease c perfrmgerr reedpeismihg outbreaks bend to be m a large seaie Thae are few irahy fatalities m Him c pcr ingcn Enterowxins simpie polypepude meieeiiiar weigqt of Maine 309 amine acid was Cys desimciim in A mihmes at 60 C c pcr ingcn Enterowxins Have aimiiamiemiih V choleme mlamwxin gtltaiiae a eahaiem increase in capillary peimeaiiiiiey Wiih niiia aeeiimiiiaiien and diarrhea gtIncreased aeereiieh ofwata39 aeaiiim aha ehiehae gtDecreased absorpum of giiieeae gtEmeeeieiaih eaiiaea aeaqiiamacieh of Viiieiia epiiheiiiim C perfringens Enterotoxins 0 About 02 7 36 pg toxing feces is found in patients suffering from C perfringens food poisoning 0 Only toxigenic types A and C seldom D of C perfringens produce enterotoxin causes gastrointestinal symptoms C perfringens Spores C perfringens spores can be isolated from healthy persons 0 These spores are probably formed in the colon rather than in the small intestines Immunity 0 After an incident of disease circulating antibodies that neutralize enterotoxin are found in the blood but not in the intestines C perfringens food poisoning does not confer immunity Reservoirs C perfringens is found in human and animal intestinal tracts and soil 0 N 50 to 100 of normal healthy humans are carriers of C perfringens Carriers excrete around 103 spores g of feces Recovering individuals shed gt 105 g Shedding Frequency 0 Shedding frequency in animals gt Swine l8 gtRats 41 gtChicken 88 60 produced toxin gtCattle 80 68 produced toxin Growth and Survival 0 Growth temperature is 65 7 47 C 0 Freezing cells at 718 C only 4 survived for 180 days 0 Freezing spores at 718 C only 11 survived for 180 days 0 Storage at 5 C more lethal than freezing at 718 C PHR 250 41706 6p Escherichia coli Class Notes PHR 150 Linda J Harris Department of Food Science and Technology University of California Davis April 18 2005 Revised for presentation by Dean 0 Cliver April 17 2006 General characteristics First characterized by Theodor Escherich over a century ago E coli is a gramnegative rod and is a member of the family Enterobacteriaceae It is the most common facultative anaerobe in the intestinal tract of humans and animals up to 108 CFU g of feces It is a member of the coliform group of organisms that are characterized by their ability to ferment lactose with the production of acid and gas Table 1 General growth parameters for E coli T r 0C pH Water activity Minimum 7 7 8 44 Optimum 35 7 40 6 7 7 0995 Maximum 44 7 46 90 7 Serolog and Nomenclature Somatic antigen 0 outermembrane protein capsular antigen K agellar antigen H 173 O antigens many unknown 0 groups 103 K antigens 56 H antigens note NM Fimbrial Fantigens can also be used but this must be done in specialized laboratories and so is not done on a routine basis Types of foodassociated enteric E coli infections Based on disease syndromes laboratory characteristics particularly their effects on tissue cultures Six Virulence groups are recognized enteroaggregative EAEC EAggEC enteropathogenic EPEC enterotoxigenic ETEC 39 Illa ic EHEC 39 39ve EIEC and diffusely adherent DAEC All cause foodborne infections although some produce active toxins once established in the host 150E6 Table 2 Some of the O serogroups associated among ve E coli virulence groups Note that some serotypes e g 0111 are listed under more than one virulence group From Jay J 1996 Modern Food Microbiology Chapman amp Hall NY EAEC EIEC EPEC ETEC EHEC 3 4 6 7 17 44 28 112 124 18 19 55 86 6 8 15 20 25 2 4 5 6 22 26 51 68 73 75 135 136 143 111 114 119 27 63 78 80 38 45 46 82 77 78 85 111 144 147 152 125 126 127 85101 115 84 88 91 103 127142162 164167 128142158 128139141 104 111 113 147 148 149 116 118 145 153 159167 153 156 157 163 Enteroaggregative E coli EAEC Some indication that EAEC can be foodborne isolated from infant feeding bottles in Japan associated an outbreak of school children and school lunches They carry a 60MDa plasmid needed for the production of fimbriae and an outer membrane protein that results in their aggregative phenotype In the laboratory these strains adhere to HEp2 cells in clumps EAEC result in a persistent diarrhea that can last for more than 2 weeks especially in children Also associated with diarrhea and weight loss in HIVinfected individuals Asymptomatic carriage may occur Model for pathogenesis involves three stages 1 initial adherence to intestinal mucosa and mucus layer 2 enhanced mucus production that leads to a biofllm on the mucosal surface 3 production of toxins that damage the mucosa and result in intestinal secretion Enteroinvasive E coli EIEC Similar to Shigella in that they enter and multiply in the colonic epithelial cells causing cell death and then spread to adjacent cells Like Shigella they possess a 120 7 l40MDa plasmid that codes for the production of several outer membrane polypeptides involved in invasiveness plasmidless strains are not invasive Profuse bloody or nonbloody diarrhea is a consequence The incubation period is between 8 and 48 h with an average of 18 h Foodborne illness has been documented They seem to be less efficient than Shigella in causing disease as the infective dose is thought to be quite high gt106 CFU The organism is atypical for E coli in that most strains are nonmotile They are unable to ferment lactose or do so only slowly and they do not produce gas from lactose anaerogenic and they are unable to decarboxylate lysine 2 150E6 Table 3 Disease associations of Virulence types of E coli Adapted from Bell C and A Kyriakides 1998 E coli A practical approach to the organism and its control in foods Chapman amp Hall Virulence type Disease Association Summary of E colthost interaction Enteroaggregative EAEC Enteroinvasive EIEC Enteropathogenic EPEC Enterotoxigenic ETEC Enterohemorrhagic EHEC Ver0 cytotoxigenic VTEC Shiga t0xigenic STEC Diffuser adherent DAEC Persistent diarrhea in children Diarrhea watery and mucoid Up to 30 grossly bloody stools Acute dysenteric diarrhea Enteritis in infants Traveler s diarrhea Acute and0r persistent profuse watery diarrhea vomiting fever Diarrhea vomiting and fever Traveler s diarrhea Acute watery diarrhea Shigellalike dysentery stools contain blood and mucus Hemolytic uremic syndrome in some cases Childhood diarrhea EAEC bind in clumps aggregates to cells of the small intestine and produce toxins Virulence factors include aggregative adherence and heatstable enterotoxin plasmid mediated EIEC invade cells in the colon and spread laterally cell to cell Virulence factors include cell invasion and intracellular multiplication plasmid and chromosomally mediated EPEC attach to intestinal mucosal cells causing cell structure alterations attaching and effacing EPEC cells invade the mucosal cells Virulence factors include attaching and effacing lesions localized adherence mediated by bundleforming pili plasmid and chromosomally mediated ETEC adhere to the small intestinal mucosa and produce toxins that act on the mucosal cells Virulence factors include adherence and heatstable 0r heatlabile toxins plasmid and chromosomally mediated EHEC attach to and efface mucosal cells and produce t0xins which cause an irreversible inhibition of protein synthesis in eukaryotic cells A subunit shows enzymatic activity B subunit binds to receptors on the surface of some tissues kidney Virulence factors include attaching and effacing adherence Shiga toxins hemolysin plasmid and chromosomally mediated Fimbrial and nonfimbrial adhesins identi ed plasmid and chromosomally mediated 3 150E6 Table 4 Characteristics of E coli related illness Adapted from Bell C and A Kyriakides 1998 E coli A practical approach to the organism and its control in foods Chapman amp Hall Viru Estimated Time to Duration of Range of symptoms lence infectious onset of illness type dose illness EIEC 10 8 7 24 h Days to Profuse diarrhea or dysentery chills fever average 11 h weeks headache muscular pain abdominal cramps EPEC 105 7 1010 17 7 72 h 6 h 7 3 days Severe diarrhea fever vomiting and average 36 h average 24 abdominal pain in infants which may persist h for more than 14 days In adults severe watery diarrhea with prominent amounts of mucus without blood and nausea vomiting abdominal cramps headache fever and chills ETEC 108 7 1010 8 7 44 h 3 7 19 days Watery diarrhea low grade fever average 26 h abdominal cramps malaise nausea When severe causes choleralike extreme diarrhea with ricewaterlike stools leading to dehydration EHEC lt100 3 7 9 days 2 7 9 days Hemorrhagic colitis HC sudden onset of 10 average 4 average 4 severe crampy abdominal pain grossly days days bloody diarrhea vomiting no fever Hemolytic uremic syndrome HUS bloody diarrhea acute renal failure in children thrombocytopenia seizures coma death Thrombotic thrombocytopenic purpura TTP similar to HUS but also fever central nervous system disorders abdominal pain gastrointestinal hemorrhage blood clots in the brain death Enteropathogenic E coli EPEC EPEC cause diarrhea in children generally under 1 year of age Asymptomatic carriers are known These strains are described as diarrheagenic E 001139 that cause illness but whose pathogenic mechanisms are not related to either heatlabile enterotoxins LT heatstable enterotoxins ST to Shigella like invasiveness or verocytotoxigenic properties They appear to destroy the microvilli without further invasion Illnesses are uncommon in temperate climates with good hygienic standards However they are still a common cause of disease in tropical countries especially among the poor Transmission fecal oral 7 food infant formula persontoperson contaminated objects 4 150E6 Foodrelated outbreaks have been rare A coffee substitute was implicated as the vehicle in a 1961 outbreak E coli O86K7H34 was isolated at high levels from the coffee substitute and from the stools of patients A waterborne outbreak was reported in 1967 near Washington DC At least 170 adults became ill over a period of several weeks E coli 0111H4 was isolated from the water supply and from the fecal samples of some patients Immunity is thought possibly to play a role in the low incidence of this type of illness A WHO report suggested that 50 of children possess antibodies to EPEC by 1 year of age which may lead to immunity as an adult Enterotoxigenic E coli ETEC Major cause of infantile diarrhea in developing countries It is the agent most frequently linked to traveller s diarrhea Humans are the principal reservoir Foods implicated in outbreaks include ready toeat items served raw or cooked but served cold Virulence Factors Plasmids encode for fimbrial adhesins or colonization factors heatlabile LT and heatstable ST toxins Heatlabile toxins of ETEC are inactivated at 60 C for 30 minutes LTI closely resembles cholera toxin LTI binds to ganglioside receptors on mammalian cell surfaces stimulates adenylate cyclase activity ultimately leading to water and electrolyte out ow into the lumen of the small intestine which results in watery diarrhea LTII is antigenically distinct but has similar biological properties ST consists of two toxic products STA and STB It appears to act mainly as an antiabsorbent rather than in a secretory fashion Withstands boiling for 15 min at 100 C Colonization factors fimbriaeflagellar 987P or K88 7 specific for swine K99 7 specific for calves lambs and swine CFNI 7 specific for humans Colonization factor antigen 1 CFNH 7 specific for humans CFNHI Enterohemorrhagic E coli QEHEC also VTECSTEC 1977 7 Vero cytotoxicity phenomenon described 1982 7 Identified as cause of human illness 1986 7 Foodbome illness dominant cause is recognized 1987 7 Natural habitat in cattle identified Mead et al 1999 Estimated 62000 cases annually 05 of all foodbome illness 85 of cases presumed to be foodbome Estimated 1843 hospitalizations 3 of all foodbome illnesses Estimated 52 deaths 29 of deaths Course of infectionduration 5 150E6 Most E coli 0157H7 predominant serotype infections are relatively mild However infections can result in hemorrhagic colitis bloody in ammation of the colon In some cases bleeding can be severe Most cases of hemorrhagic colitis recover 6 7 8 days after onset but patients may be hospitalized if symptoms are more severe The yup may be A J and inappropriate or unnecessary procedures may result Of those infected with E coli 0157H7 it is estimated that 50 will not visit a physician and will fully recover An estimated 32 are ill enough to visit a physician and fully recover 154 are hospitalized and fully recover 23 are hospitalized and die and 03 are hospitalized and develop chronic kidney failure From Food Safety Information on foodbome illnesses and food safety reducing the threat of foodbome illnesses May 1996 The consequences of hemolytic uremic syndrome are very severe leading to lifethreatening disease characterized by red blood cell destruction kidney failure and neurological complications such as seizures and strokes Transmission Cattle are thought to be a major reservoir of E coli 0157H7 Other ruminants are also thought to be sources At least one outbreak has been associated with deer meat To date a large number of outbreaks have been associated with meat or meat products especially undercooked comminuted meat In other instances outbreaks there has been cross contamination from food handlers or from raw meats to cooked or readytoeat foods 7 melons salads mayonnaise In some produceassociated outbreaks contamination from the soil as a result of fertilization with manure or grazing of orchards has also been suggested as a mode of transmission Fruit ies have also been shown to transfer E 001139 from a contaminated source to apples Estimated impact FoodNet Data Rate per 100000 1996 27 1997 23 1998 28 1999 21 2000 29 2002 17 2002 16 2003 23 2004 09 There are an estimated 10000 7 20000 cases ofE colz39 0157H7 disease each year in the Us with an estimated 19 7 37 deaths It is estimated that 80 of human illness due to E coli 0157H7 is attributed to food and that the total costs of foodbome E coli 0157H7 range from 02 7 06 billion annually Virulence factors All strains of EHEC are capable of producing Shiga toxin 1 Stx1Verotoxin 1 VTl andor Shiga toxin 2 Stx2Verotoxin 2 VT2 The toxin is composed of a single A subunit of 32 kDa and five B subunits of 77 kDa each The B subunits bind to specific receptors Gb3 on the surface of eucaryotic cells Endothelial cells in the colon and the kidney have high levels of Gb3 The A subunit acts as a N glycosidase that inactivates the 28S ribosome effectively blocking protein synthesis The presence of toxin alone is not sufficient to cause yup Enter 39 39J 39 r J quot an outermembrane protein encoded by the plasmidassociated gene eae is thought to be involved in attachment Outbreaks More than any organism other than Clostridium botulinum E coli 0157H7 has had a major impact on food regulations in the Us 6 150E6 A number of important outbreaks caused by EHEC strains are listed in Table 5 The rst outbreaks linked to E coli Ol57H7 were recorded in 1982 Both were associated with hamburgers served from the same restaurant chain in Oregon and Michigan Retrospective studies suggest that an earlier outbreak associated with apple cider occurred in Ontario in 1980 An outbreak in 1988 involved precooked patties purchased in the USDA school lunch program Identi cation of E coli in these products lead to increases in the required cook time for USDA inspected products and ultimately to the adoption of higher cooking temperatures by the state of Washington Table 5 Some important reported food and waterborne outbreaks caused by EHEC Year Place Implicated food IllDeaths 1980 Ontario Apple cider 140 1982 Oregon Ground beef 260 Michigan 210 1984 North Carolina Persontoperson 360 1985 Ontario Sandwiches 73 19 Persontoperson 1988 Minnesota Ground beef 540 precooked 1989 Missouri Water 2434 1991 Massachusetts Apple cider 230 1993 WM CAN V ID Ground beef gt500 WA 3 gt200 CAN V ID 1993 Oregon Mayonnaise 190 Cantaloupe 100 1994 California Fermented salami 180 Washington 1995 Australia 01 1 1 Fermented salami 231 1996 Illinois Red leaf lettuce 270 Connecticut 180 1996 Japan School lunches gt1000010 1996 Paci c coast Unpasteurized apple juice 661 1996 Scotland Meat pies gt25016 Case Studies Hamburgers 1993 Product type Cooked hamburger patties from a fast food restaurant Year 1992719 93 7 150E6 Location Western US Levels Estimated 1 7 15 cells per gram 40 7 600 cells per raw hamburger patty Extent gt700 people affected 195 hospitalized 55 HUS or TTP 4 deaths approximately 10 of cases secondary from persontoperson contact Comments Inadequate cooking of contaminated hamburger patties While this outbreak was the largest E coli 0157H7 outbreak in the US many smaller outbreaks have also been associated with undercooked hamburger patties Control Options Procedures in place to ensure minimal contamination of raw materials Vendor certi cation Procedure in place to ensure destruction of E coli 0157H7 during cooking including de ned process times and temperatures A 1988 outbreak involving precooked patties lead to a rapid FSIS policy change on December 27 1988 This increased the cooking temperature from 140 to 160 F 60 to 711 C Opposition to the ruling was expressed as the high temperature often resulted in a very dry unpalatable hamburger With consideration of further comments from the industry as well as research results published in 1991 these policy changes were modi ed on June 5 1990 to lower temperatures and more cooking options In mid1992 the USDA study and policy change prompted Washington State to increase the required cooking temperature for hamburgers to 155 F 683 C Although this is a requirement undercooked hamburgers can be ordered if speci cally requested The FDA changed its policy in the Food Code during the 1993 outbreak to match the Washington State requirement Before the January 1993 JackInTheBox outbreak in the Paci c Northwest E coli 0157H7 and related strains were considered by many to be relatively rare During the outbreak the FDA increased its recommended cook temperature from 140 F to 155 F Shortly after this outbreak July 1996 changes were made to the USDA meat inspection regulations Most controversial was the de nition of E coli 0157H7 as an illegal adulterant in raw ground meat Although FDA did not follow suit the USDA regulation has effectively resulted in this organism being considered an illegal adulterant if found at all in the food supply In February 1999 the USDA approved irradiation in red meats as a means of controlling E coli 0157H7 and other pathogens Consumers are recommended to cook hamburgers to 160 F as measured by a thermometer Unpasteurized Apple Cider 1996 Product type Unpasteurized apple juice M 1996 Location Western US Levels Unknown very low Extent 66 cases one death Comments Juice not pasteurized Source of E coli 0157H7 in apple cider unclear Earlier outbreaks suggested route was use of dropped apples with possible close proximity to cattle pastures or deer prevalent in the orchards Supplier contracts apparently stipulated no drops Control Options At this time pasteurization is recommended for susceptible populations Investigations are underway to try to determine alternative Fr 39 to 39 39 39 an reduction of E coli 0157H7 currently de ned as 5log reduction 1 On July 8 1998 FDA published the nal rule for the labeling of freshjuices and extended the comment period for the HACCP proposed rule For apple cider producers the nal ruling stated that if 8 150E6 the juice was not treated to achieve a 5log reduction of the pertinent pathogen it was required to have a warning label on the bottle or a warning placard at the point of sale This option of having a warning placard in place ofa wa1ning label on the bottle itself was ONLY for 199871999 As of September 8 1999 all fresh juices not treated to achieve a 5log reduction of the pertinent pathogen MUST have a warning label on the bottle The warning label must read as follows WARNING This product has not been pasteurized and therefore may contain harmful bacteria that can cause serious illness in children the elderly and persons with weakened immune systems The final rule for mandatory HACCP requirements for the juice industry was published in January 2001 Survival in acidic foods E coli 0157H7 survives but doesn t grow in many acidic foods Because of the low infective dose the organism does not need to multiply in the food 7 just survive Outbreaks have been associated with yogurt UK 1991 uncooked semidry fermented sausage Australia 1995 7 OlllNM California 1994 and mayonnaise Oregon 1993 Survival is extended at refrigerated temperatures and is known at frozen temperatures in ground meat products Populations of E coli 0157H7 did not significantly decrease in hamburger stored over 9 months at 20 C E coli is notheat resistant and is relatively easily killed during cooking or pasteurization The FDA also proposed voluntary Good Agricultural Practices after a series of outbreaks associated with contaminated fruits and vegetables C yclospora from imported raspberries 199571997 E coli 0157H7 from lettuce 1996 and hepatitis A from frozen strawberries 1997 These are the first times guidelines for sanitary procedures have been provided at the farm level Further Reading Bell C and A Kyriakides 1998 E coli A practical approach to the organism and its control in foods Blackie Academic amp Professional New York Buchanan R L and M P Doyle 1997 Foodbome disease significance of Escherichia coli 0157H7 and other enterohemorrhagic E coli Food Technol 51106976 Fratamico P M J L Smith and R L Buchanan 2002 Escherichia coli p 797101 In D O Cliver and H P Riemann ed Foorbome diseases 2quotd ed Academic Press London Fratamico P M and J L Smith 2006 Escherichia coli p 2057258 In Riemann H P and D O Cliver eds Foodbome Infections and Intoxications 3d ed Academic Press Elsevier London Amsterdam Grif n P M and R V Tauxe 1991 The epidemiology of infections caused by Escherichia coli 0157H7 other enterohemorrhagic E coli and the associated hemolytic uremic syndrome Epidemiol Rev 136097 9 150E6 10 Slutsker L A A Ries K D Green J G Wells L Hutwanger and P M Griffin 1997 Escherichia coli 0157H7 diarrhea in the United States clinical and epidemiologic features Annals Int Med 126505513 Web Sites of Interest check dates Juice HACCP httpwww cfsan fda onV 39 39 39 html FDA Bad Bug Book ETEC httpVmcfsanfdag0Vm0Wchapl3html EPEC hnyvmcfsanfdagovNmowchapl4html E coli 0157H7 hngvmcfsanfdag0Vm0Wchapl html EIEC http Vmcfsanfda govNmowchap l 6html Ecomonics of E coli illness httpwwwersusdagovbriefingZF00dbomeDiseaseecoliindexhtm FDA BAM Manual 7 methods httpwwwcfsanfdagovNebambamtochtml Draft Risk Assessment Preliminary pathways and data for a risk assessment of Eshcerichz39a colz39 0157H7 in beef httpwwwfsisusda govOPHSecolrisldchapterlpdf Seafood Toxins PHR 250 Seafood Toxins I Dr Robert Price has retired amp died I Excerpts from the US FDA Bad Bug Book I Order of presentation is according to my perception of relative risks in the US Selected Illnesses I Shellfishassociated toxins I Scombroid poisoning ICiguatera poisoning ITetrodotoxin pufferfish Shell shassociated toxlns I Paralytic Shellfish Poisoning PSP I Diarrheic Shellfish Poisoning DSP I Neurotoxic Shellfish Poisoning NSP IAmnesic Shellfish Poisoning ASP Paralytic SP I PSP predominantly neurological tingling burning numbness drowsiness incoherent speech and respiratory paralysis IOnset in 05 2 hr death from respiratory or circulatory failure Saxitoxin PSP H2 VDK 39 H H EH STX R1 R2 R 2 R2 Y STX H N N NH GTXll H use 2 0H e39rxm H use H 9 DH NeoSTX uH H GTXl uH H use R2 R3 GTXIV uH use H Paralytic SP I Mussels clams cockles amp scallops I Detecting PSP toxins saxitoxin etc mouse bioassay or HPLC I Beach postings language Diarrheic SP I Mild GI disorder nausea vomiting diarrhea amp abdominal pain with chills headache and fever I Onset 05 2 or 3 hr lasts 3 days complete recovery Okadaic acid DSP H CH3 0 o J 0 0 Kim Hac Ho x o 0 H30 0H 0 lo OH CH3 H CH3 plus others Diarrheic SP I Mussels oysters amp scallops I Detecting DSP toxin okadaic acid mouse bioassay unreliable HPLC or ELISA used Neurotoxic SP I GI amp neurological symptoms tingling amp numbness of lips tongue amp throat muscular aches dizziness reversal of the sensations of hot amp cold diarrhea amp vomiting I Onset mins hrs duration hrs days complete recovery Brevetoxin NSP Nourotoxlc SP I Shellfish harvested along Florida coast amp Gulf of Mexico I Detecting NSP togtltin brevetogtltin no method mentioned Amnoslc SP I GI disorders vomiting diarrhea abdominal pain amp neurological pro confusion memory loss disorientation seizure coma serious sometimes fatal in elderly Domoic acid ASP Amneslc SP I GI onset 24 hr neurological nset 48 hr longterm neurological effects I Mussels I Detection of ASP togtltin domoic acid by HPLC Soombroid Poisoning ITingling or burning in mouth rash on upper body drop in blood pressure IFreq uently headache amp itching skin Scombroid Poisoning IOnset immediate 0 min duration N3 hr rarely several days IMay progress to nausea vomiting amp diarrhea Scombroid Poisoning I Hospitalization elderly or Scombrotoxin precursor H impaired patients 0 N o I Mmcs allergy EH CODH iiii2 Scombroid Poisoning Ciguatera ITunas eg skipjack amp yellow n mahi mahi bluefish sardines mackerel amberjack amp abalone other foods Swiss cheese I FDA test for histamine other toxins may also be involved I Combination of GI nausea vomiting diarrhea neurological perioral numbness amp tingling may spread to extremites amp cardiovascular disorders Ciguatera I Onset 6 hr lasts days weeks months years relapses possible I Warmwater marine nfish groupers barracudas snappers jacks mackerel triggerfish sporadic Ciguatoxin Glguatora ICiguatera toxins difficult to extract amp purify mouse bioassay may be replaced by EIA Totrodotoxln ISIight numbness of lips amp tongue at 20 min 3 hr IIncreasing paraesthesia IPossible headache epigastric pain nausea d39arrhea vomiting reeling or difficulty in walking I2d stage increasing paralysis dysphonia dyspnea cyanosis and hypotension amp extremItIe sensations of lightness or I Diagnosis only floating Tetrodotoxin Tetrodotoxin IIncreased paralysis convulsions mental impairment cardiac arrhythmia IVictim completely paralyzed ay be conscious amp completely lucid until shortly before death at 4 6 hr range 20 min 8 hr Tetrodotoxin Tetrodotoxin IPufferfish from IndoPacific ocean regions 20 spp toxin distributions differ gonads viscera skin ITesting mouse PSP bioassay HPLC amp GCMS methods await validation Microbial Decontamination USDA 1996 Food Safety amp IPathogen Reduction amp Antimicrobial Hazard Analysis amp Critical Control Points HACCP Interventlons Rule Mega Regquot Dean 0 Cliver IMandated SSOPs graduated implementation of HACCP Mega Reg 1996 Mega Reg 1996 ICOmpanieS to design their Carcass surface swab OWn plans samples One mandated CCP no Generic 5 CO39 visible fecal ingesta quantitative milk depOSits 0 Cgrcass ISamonela qualitative surface others optional Mega Reg 1996 Interventions IE col0157H7 only I Sanitation illegal adulterant in raw ground beef only 39 Tr39mrT39ng New development 39 Was 39 9 recalls of trimmings used I Carcass treatments to make ground beef due Packaging to 0157 presence Sanitation uMidIine incision etc uHide pulling Evisceration Washing ICarcass washing with tap water was traditional Hot water now generally used Trimming uKnife trimming of carcass surface to remove visible deposits quinions of inspectors vs workers Carcass treatments uOrganic acids uSteam PasteurizationTM System Irradiation pasteurization IOzonation Hydrogen peroxide Carcass treatments ICetylpyridinium chloride ISodium chloride uAcidified sodium chlorite Sanova Process Carcass treatments uChlorine washes Trisodium phosphate Lactates Packaging color 02 adsorption eg potassium permanganate IMAP 80 OZ 20 CO2 Vacuum Summary IUSDA s version of HACCP CCPs uSheIf life extension FUNGI AND MYCOTOXINS Mehrdad Tajkarimi DVM PhD University of CaliforniaDavis PHR 250 07 Mehrdad Talkaiimi DVM PhD VMPHR 25 m 00 Dans Introduction 0 Myco means mold and toxin represents poEon 0 Mainly low molecular weight proteins 0 Under proper environmental conditions temperature moisture oxygen mycotoxin levels become high MehmadTalkanm DVM PhD VMPHR 25 m 00 Davis Mycotoxins Some mycotoxins Lethal effects Cause speci c diseases Effect on the immune system Act as allergens or irritants No known effect on human and animal health Act on other microorganisms such as penicillin39s antibiotic ac ion Effective in animal feed or food and sometimes both 0 Human and animal health has been proven Mehrdad Talkaiimi DVM PhD VMPHR 25 m 00 Dans History 0 Ergotism and mushrom poisoning oAIimentary toxic aleukia ATA with more than 5000 deaths caused by trichothecene mycotoxins in grain in the USSR late in World War II cm 1960 in which 100000 turkeys died of an unknown disease MehmadTalkanm DVM PhD VMPHR 25 m 00 Davis Mycotoxin production and occurrence Can occur 0 In the field Aspergillus flavus and some Fusarium species 0 Preharvest some Fusarium species and Tricllotllecium 0 Processing 0 Transportation 0 Storage Penc17ium are mainly found Mehrdad Talkaiimi DVM PhD VMPHR 25 m 00 Dans A atoxin 0 Can be produced by three species of AspergYlus A avus A parasrims and the rare A l70l77U5 0 Aflatoxin B1 is a potent liver carcinogen and DNAdamaging agent 0 Aflatoxins are very heat resistant and are difficult to remove from foods and feeds 0 Aflatoxins M1 and M2 are the hydroxylated metabolites of aflatoxins B1 and B2 and can be found in milk or milk products MehmadTalkanm DVM PhD VMPHR 25 m 00 Davis Ochratoxins 0 Prod uced by Asperglus and Penicillium 0 Occurs primarily In cereal grains and mixed feeds but it can also be found In beans coffee fruit juices nuts olives cl7eese fI39sl7 pork milk powder pepper Wine and beer Mehvdad Talkanmi DVM PhD VMPHR 25 n7 uc pm Fumonisins 0 Produced primarily by Fusariun verticilioi es 0 Most common fungi colonizing corn and cornbased foods as well as other grains such as sorghum and rice throughout the world 0 Several reports of a possible role in the etiology of human esophageal cancer MahmadTalkanm DVM PhD VMPHR 25 n7 uc Davis Trichothecenes 0 Toxic metabolites produced in the genus Fusariun 0 Affect many organs such as the gastrointestinal tract and the hematopoietic nervous 39mmune hepatobiliary and cardiovascular systems 0 Alimentary toxic aleukia ATA 0 TZ toxin is a highly toxic type A TCTC Mehvdad Talkanmi DVM PhD VMPHR 25 n7 uc pm Deoxynivalenol 0 Produced primarily by F gramnearum 0 Feed refusal and emesis in swine named vomitoxin 0 It is considerably less toxic than most other mycotoxins MahmadTalkanm DVM PhD VMPHR 25 n7 uc Davis Sterigmatocystin 0 Produced by fungi in the Asperglus Bipolars and Chaetomium genera and by Penicillium luteum 0 Precursor in the metabolic pathway to aflatoxin production but is toxic in its own right though not as potent as aflatoxin B1 Mehvdad Talkanmi DVM PhD VMPHR 25 n7 uc pm Genus Penicillium 0 Cyclochlorotine luteoskyrin and rugulosin are hepatotoxins mycotoxins 0 patulin penicillic acid citrinin cyclopiazonic acid citreoviridin and xanthomegnin 0 Patulin is often found in damaged apples apple juice apple cider 0 At least 10 countries have regulatory limits MahmadTalkanm DVM PhD VMPHR 25 n7 uc Davis Mycotoxin preventive measures Toxin formation I Using resistant varieties I Good agricultural practice I Drying grain to less than 10 13 I Antifungal agents and phenolic antioxidants and antibiotics Mehvdad Talkanml DVM PhD VMPHR 25 m 00 um Mycotoxin preventive measures Monitoring programs to avoid human ure I Monitoring and measures of mycotoxins in food and animal feed I TLC HPLC and GC techniques I New chemical methods I Capillary electrophoresis I Fluorescence polarization I Immunoassay simple approach I Biosensors MahmadTalkanm DVM PhD VMPHR 25 m 00 Dayls Mycotoxin preventive measures Remove mycotoxins from commodities I Chemical detoxifiers including acids alkalis aldehydes I Oxidizing agents and gases such as chlorine sulfur dioxide NaNOz ozone ammonia are used for aflatoxins fumonisin and trichothecene Mehvdad Talkanml DVM PhD VMPHR 25 m 00 um Mycotoxin preventive measures Cooking and pasteurization I Do not destroy mycotoxins generally I Extrusion cooking is effective for detoxifying DON and roasting has some effect in reducing 0A in coffee MahmadTalkanm DVM PhD VMPHR 25 m 00 Dayls Miscellaneous fungi Ergot I Convulsive type convulsions tingling sensation of muscles and sometimes the entire body IS racked by European and most other countries limit of 01 02 In the US wheat or rye with 03 sclerotia is considered unsafe and oats triticale or barley having more 1 I Ethiopian epidemic in 1978 from ergotinfested oats Approximately 50 of the affected persons died I Similar problems occurred in India in the 197039s Mehvdad Talkanml DVM PhD VMPHR 25 m 00 um Mushrooms I Amanita phalloidesDeath Ca p I Amanita muscarina I Caprimls atramenta 39us I Galerina spp I Gyromitra esculenta I Psiocybe mexicana I Quorn39 MahmadTalkanm DVM PhD VMPHR 25 m 00 Dayls Amanita phalloides Death Ca p I Contains 2 3 mg of amatogtltins per gram of dry ssue I A single mushroom can kill an adult human I Vomiting nausea abdominal pain and bloody diarrhea that develops within 6 24 hours I These signs may lessen for a short period of 12 24 hours followed by confusion delirium seizures and coma I The mortality rate in humans is 10 40 Mehvdad Talkavimi DVM PhD VMPHR 25 n7 uc 0m Amanita muscarina I Death does not usually occur when these are the only toxins in the poisonous mushrooms I Fly agaric also contains amatogtltins and phallotogtltins I Fatal combination of symptoms may occur MahmadTalkanm DVM PhD VMPHR 25 n7 uc Davis Coprinus atramentarius I Symptoms typically begin about 30 minutes after drinking alcohol I May occur for as long as 5 days after mushroom ingestion Mehvdad Talkavimi DVM PhD VMPHR 25 n7 uc 0m Galerina spp I Small brownish mushrooms commonly growing on wood I These mushroom are easily confused with the edible twotoned Pholiota uemeromyces mutabI39s that also grows on wood in clumps MahmadTalkanm DVM PhD VMPHR 25 n7 uc Davis Gyromitra esculenta I Contains gyromitrin I Causes a bloated feeling nausea vomiting watery or bloody diarrhea abdominal pain muscle cramps faintness and loss of motor coordination I Typically occur 6 12 hours after eating the mushrooms I Illness can progress to convulsions coma and death Mehvdad Talkavimi DVM PhD VMPHR 25 n7 uc 0m Psiocybe mexicana I Megtltican mushrooms magic mushrooms or shrooms I Symptoms begin about 30 60 minutes after ingestion I include pleasant or apprehensive mood unmotivated laughter and hilarity compulsive movements muscle weakness drowsiness hallucinations and finally sleep I Death in small children MahmadTalkanm DVM PhD VMPHR 25 n7 uc Davis PHR 250 42307 7p SEAFOOD TOXINS Dean 0 Cliver Our resident expert on this subject Dr Robert Price has retired and since died He based his presentation on excerpts from the US FDA Bad Bug Bookquot and for the time being I shall do the same The URLs of the appropriate sections are 0 Shell shassociated toxins httpwwwcfsanfdagovmowchap37html O Scombroid poisoning httpwwwcfsanfdagovmowchap38html O Ciguatera poisoning httpwwwcfsanfdagovmowchap36html O Tetrodotoxin puffer sh httpwwwcfsanfdagovmowchap39html These are presented according to my perceptions of their relative risks to US consumers most to least risk Links have been deleted but are available in the online originals at the FDA web site Bibliography Johnson E A and E J Schantz 2002 Seafood toxins pp 211 230 In Cliver D 0 and H P Riemann eds 2002 Foodbome Diseases 2d ed Academic Press London Johnson E A and E J Schantz 2006 Miscellaneous natural intoxications pp 663 709 In Riemann H P and D O Cliver eds Foodborne Infections and Intoxications 3d ed Academic Press ElseVier London Amsterdam 250G7 2 VARIOUS SHELLFISH ASSOCIATED TOXINS 1 Name of the Organism Various Shell shAssociated poisoning is caused by a group of toxins elaborated by planktonic algae dino agellates in most cases upon which the shell sh feed The toxins are accumulated and sometimes metabolized by the shellfish The 20 toxins responsible for paralytic shell sh poisonings PSP are all derivatives of saxitoxin Diarrheic shell sh poisoning DSP is presumably caused by a group of high molecular weight polyethers including okadaic acid the dinophysis toxins the pectenotoxins and yessotoxin Neurotoxic shell sh poisoning NSP is the result of exposure to a group of polyethers called brevetoxins Amnesic shell sh poisoning ASP is caused by the unusual amino acid domoic acid as the contaminant of shell sh 2 Nature of Acute Disease Types of Shell sh Poisoning Paralytic Shell sh Poisoning PSP Diarrheic Shell sh Poisoning DSP Neurotoxic Shell sh Poisoning NSP Amnesic Shell sh Poisoning ASP 3 Nature of Disease Ingestion of contaminated shell sh results in a wide variety of symptoms depending upon the toxinss present their concentrations in the shell sh and the amount of contaminated shell sh The yup 39 A with DSP NSP and ASP are less well characterized than those of PSP 0 PSP the effects are predominantly neurological and include tingling burning numbness drowsiness incoherent speech and respiratory paralysis O DSP is primarily observed as a generally mild gastrointestinal disorder ie nausea vomiting diarrhea and abdominal pain accompanied by chills headache and fever 0 Both gastrointestinal and neurological symptoms characterize NSP including tingling and numbness of lips tongue and throat muscular aches dizziness reversal of the sensations of hot and cold diarrhea and vomiting 0 ASP is characterized by gastrointestinal disorders vomiting diarrhea abdominal pain and neurological problems confusion memory loss disorientation seizure coma 4 Diagnosis of Human Illness Diagnosis of shell sh poisoning is based entirely on observed symptomatology and recent dietary history 5 Associated Foods All shell sh lterfeeding molluscs are potentially toxic However PSP is generally associated with mussels clams cockles and scallops DSP with mussels oysters and scallops NSP with shell sh harvested along the Florida coast and the Gulf of Mexico ASP with mussels 250G7 3 6 Relative Frequency of Disease Good statistical data on the occurrence and severity of shellfrsh poisoning are largely unavailable which undoubtedly re ects the inability to measure the true incidence of the disease Cases are frequently misdiagnosed and in general infrequently reported Of these toxicoses the most serious from a public health perspective appears to be PSP The extreme potency of the PSP toxins has in the past resulted in an unusually high mortality rate 7 Course of Disease and Complications 0 PSP Symptoms of the disease develop fairly rapidly within 05 to 2 hours after ingestion of the shellfrsh depending on the amount of toxin consumed In severe cases respiratory paralysis is common and death may occur if respiratory support is not provided When such support is applied within 12 hours of exposure recovery usually is complete with no lasting side effects In unusual cases because of the weak hypotensive action of the toxin death may occur from cardiovascular collapse despite respiratory support 0 DSP Onset ofthe disease depending on the dose oftoxin ingested may be as little as 30 minutes to 2 to 3 hours with symptoms of the illness lasting as long as 2 to 3 days Recovery is complete with no after effects the disease is generally not life threatening O NSP Onset of this disease occurs within a few minutes to a few hours duration is fairly short from a few hours to several days Recovery is complete with few after effects no fatalities have been reported 0 ASP The toxicosis is characterized by the onset of gastrointestinal symptoms within 24 hours neurological symptoms occur within 48 hours The toxicosis is particularly serious in elderly patients and includes symptoms reminiscent of Alzheimer39s disease All fatalities to date have involved elderly patients 8 Target Populations All humans are susceptible to shellfrsh poisoning Elderly people are apparently predisposed to the severe neurological effects of the ASP toxin A disproportionate number of PSP cases occur among tourists or others who are not native to the location where the toxic shellfrsh are harvested This may be due to disregard for either offrcial quarantines or traditions of safe consumption both of which tend to protect the local population 9 Food Analysis The mouse bioassay has historically been the most universally applied technique for examining shellfrsh especially for PSP other bioassay procedures have been developed but not generally applied Unfortunately the dosesurvival times for the DSP toxins in the mouse assay uctuate considerably and fatty acids interfere with the assay giving falsepositive results consequently a suckling mouse assay that has been developed and used for control of DSP measures uid accumulation after injection of the shellfrsh extract In recent years considerable effort has been applied to development of chemical assays to replace these bioassays As a result a good high performance liquid chromatography HPLC procedure has been developed to identify individual PSP toxins detection limit for saxitoxin 20 fg 100 g of meats 02 ppm an excellent HPLC procedure detection limit for okadaic acid 400 ng g 04 ppm a commercially available immunoassay detection limit for okadaic acid l fg 100 g of meats 001 ppm for DSP and a 250G7 4 totally satisfactory HPLC procedure for ASP detection limit for domoic acid 750 ng g 075 ppm 10 Selected Outbreaks O MMWR 4010 1991 and Errata Notice MMWR 4014 1991 Paralytic shell sh poisoning PSP is a foodborne illness caused by consumption of shell sh or broth from cooked shell sh that contain either concentrated saxitoxin an alkaloid neurotoxin or related compounds This report summarizes outbreaks of PSP that occurred in Massachusetts and Alaska in June 1990 0 PSP is associated with relatively few outbreaks most likely because of the strong control programs in the United States that prevent human exposure to toxic shell sh That PSP can be a serious public health problem however was demonstrated in Guatemala where an outbreak of 187 cases with 26 deaths recorded in 1987 resulted from ingestion of a clam soup The outbreak led to the establishment of a control program over shell sh harvested in Guatemala 0 The occurrence of DSP in Europe is sporadic continuous and presumably widespread anecdotal DSP poisoning has not been con rmed in US seafood but the organisms that produce DSP are present in US waters An outbreak of DSP was recently con rmed in Eastern Canada Outbreaks of NSP are sporadic and continuous along the Gulf coast of Florida and were recently reported in North Carolina and Texas 0 ASP rst came to the attention of public health authorities in 1987 when 156 cases of acute intoxication occurred as a result of ingestion of cultured blue mussels M ytz39lus edulz39s harvested off Prince Edward Island in eastern Canada 22 individuals were hospitalized and three elderly patients eventually died 11 Education and Background Resources Loci index for genome Gonyaulax spp Available from the GenBank Taxonomy database which contains the names of all organisms that are represented in the genetic databases with at least one nucleotide or protein sequence 12 Molecular Structural Data These structures are linked to the online original Dinophysis Toxin Brevetoxin Saxitoxin Okadaic Acid Domoic Acid Yesserotoxin Pectenotoxin 250G7 5 SCOMBROTOXIN 1 Name of the Organism Scombrotoxin 2 Nature of Acute Disease Scombroid Poisoning also called Histamine Poisoning Scombroid poisoning results from eating foods that contain high levels of histamine and possibly other vasoactive amines and compounds Histamine and other amines are formed by the growth of certain bacteria and the subsequent action of their decarboxylase enzymes on histidine and other amino acids in food either during the production of a product such as Swiss cheese or by spoilage of foods such as shery products particularly tuna or mahi mahi However any food that contains the appropriate amino acids and is subjected to certain bacterial contamination and growth may lead to scombroid poisoning when ingested 3 Nature of Disease Initial symptoms may include a tingling or burning sensation in the mouth a rash on the upper body and a drop in blood pressure Frequently headaches and itching of the skin are encountered The symptoms may progress to nausea vomiting and diarrhea and may require hospitalization particularly in the case of elderly or impaired patients Mimics allergy 4 Diagnosis of Human Illness Diagnosis of the illness is usually based on the patient s symptoms time of onset and the effect of treatment with antihistamine medication The suspected food must be analyzed within a few hours for elevated levels of histamine to con rm a diagnosis 5 Associated Foods Fishery products that have been implicated in scombroid poisoning include the tunas e g skipjack and yellowfin mahi mahi bluefish sardines mackerel amberjack and abalone Many other products also have caused the toxic effects The primary cheese involved in intoxications has been Swiss cheese The toxin forms in a food when certain bacteria are present and time and temperature permit their growth Distribution of the toxin within an individual fish fillet or between cans in a case lot can be uneven with some sections of a product causing illnesses and others not Neither cooking canning or freezing reduces the toxic effect Common sensory examination by the consumer cannot ensure the absence or presence of the toxin Chemical testing is the only reliable test for evaluation of a product 6 Relative Frequency of Disease Scombroid poisoning remains one of the most common forms of fish poisoning in the United States Even so incidents of poisoning often go unreported because of the lack of required reporting a lack of information by some medical personnel and confusion with the symptoms of other illnesses Difficulties with underreporting are a worldwide problem In the United States from 1968 to 1980 103 incidents of intoxication involving 827 people were reported For the same period in Japan where the quality of fish is a national priority 42 incidents involving 4122 people were recorded Since 1978 two actions by FDA have reduced the frequency of 250G7 6 intoxications caused by speci c products A defect action level for histamine in canned tuna resulted in increased industry quality control Secondly blacklisting of mahi mahi reduced the level of fish imported to the United States 7 Course of Disease and Complications The onset of intoxication symptoms is rapid ranging from immediate to 30 minutes The duration of the illness is usually 3 hours but may last several days 8 Target Populations All humans are susceptible to scombroid poisoning however the symptoms can be severe for the elderly and for those taking medications such as isoniazid Because of the worldwide network for harvesting processing and distributing shery products the impact of the problem is not limited to speci c geographical areas of the United States or consumption pattern These foods are sold for use in homes schools hospitals and restaurants as fresh frozen or processed products 9 Food Analysis An of cial method was developed at FDA to determine histamine using a simple alcoholic extraction and quantitation by uorescence spectroscopy There are other untested procedures in the literature 10 Selected Outbreaks O MMWR 389 1989 Scombroid sh poisoning is an acute syndrome resulting from consumption of sh containing high levels of histamine This report summarizes inve tioatinn oftwo quot 39 of 39 39 39 fish r 39 39 in Illinois and South Carolina in 1988 O MMWR 37291988 In July 1987 state and local public health of cials in New Mexico investigated two cases of 39 39 39 sh r 39 39 39 39 39 r 39 39 in persons living in Albuquerque A husband and wife had become ill within 45 minutes after eating dinner Their symptoms included nausea vomiting diarrhea headache fever ushing and rapid pulse rate An investigation by the Albuquerque Environmental Health Department found that the couple had shared a meal of grilled mahi mahi pasta salad water and wine Their dog had eaten some of the sh and had vomited Both of the patients had been treated with Benadryl activated charcoal and ipecac in a hospital emergency room Their symptoms resolved within 36 hours of onset of illness 0 MMWR 35161986 Between December 31 1985 and January 4 1986 three restaurants in Alabama and Tennessee received complaints of illness from nine customers and one employee who ate Paci c amberj ack sh also called yellowtail or kahala One restaurant cook who did not eat the sh reported a transient red rash on the hands shortly after handling the sh 111 persons reported no other menu items in common The sh meals were prepared by grilling or frying Three people sought medical evaluation One had diastolic hypotension and one had bronchospasm All three were diagnosed as having food or sh allergy and were treated with an antihistamine The symptoms of scombroid sh poisoning resemble those ofa 39 39 39 reaction 39J 39 39 is r 250G7 7 a response to toxic byproducts not an allergic reaction to sh Several large outbreaks of scombroid poisoning have been reported In 1970 some 40 children in a school lunch program became ill from imported canned tuna In 1973 more than 200 consumers across the United States were affected by domestic canned tuna In 1979 1980 more than 200 individuals became ill after consuming imported frozen mahi mahi Symptoms varied with each incident In the 1973 situation of the interviewed patients 86 experienced nausea 55 diarrhea 44 headaches and 32 rashes O Other incidents of intoxication have resulted from the consumption of canned abalonelike products canned anchovies and fresh and frozen amberjack bluefish sole and scallops In particular shipments of unfrozen fish packed in refrigerated containers have posed a significant problem because of inadequate temperature control 11 Education and Background Resources Loci index for genome Available from the GenBank Taxonomy database which contains the names of all organisms that are represented in the genetic databases with at least one nucleotide or protein sequence 12 Molecular Structural Data This structure is linked to the online original Scombroid Toxin 250G7 8 CIGUATERA 1 Name of the Organism Ciguatera 2 Nature of Acute Disease Ciguatera Fish Poisoning Ciguatera is a form of human poisoning that results from eating subtropical and tropical marine n sh which have accumulated naturally occurring toxins through their diet The toxins are known to originate from several dino agellate algae species that are common to ciguatera endemic regions in the lower latitudes 3 Nature of Disease Manifestations of ciguatera in humans usually involve a combination of gastrointestinal neurological and cardiovascular disorders Symptoms de ned within these general categories vary with the geographic origin of toxic fish 4 Diagnosis of Human Illness Clinical testing procedures are not presently available for the diagnosis of ciguatera in humans Diagnosis is based entirely on symptomology and recent dietary history An enzyme immunoassay EIA designed to detect toxic sh in eld situations is under evaluation by the Association of Of cial Analytical Chemists AOAC and may provide some measure of protection to the public in the future 5 Associated Foods Marine n sh most commonly implicated in ciguatera sh poisoning include the groupers barracudas snappers jacks mackerel and trigger sh Many other species of warmwater shes harbor ciguatera toxins The occurrence of toxic sh is sporadic and not all sh of a given species or from a given locality will be toxic 6 Relative Frequency of Disease The relative frequency of ciguatera sh poisoning in the United States is not known The disease has only recently become known to the general medical community and there is a concern that incidence is largely underreported because of the generally nonfatal nature and short duration ofthe disease 7 Course of Disease and Complications Initial signs of poisoning occur within 6 hours after consumption of toxic sh and include perioral numbness and tingling paresthesia which may spread to the extremities nausea vomiting and diarrhea Neurological signs include intensi ed paresthesia arthralgia myalgia headache temperature sensory reversal and acute sensitivity to temperature extremes vertigo and muscular weakness to the point of prostration Cardiovascular signs include arrhythmia bradycardia or tachycardia and reduced blood pressure Ciguatera poisoning is usually selflimiting and signs of poisoning often subside within several days from onset However in severe cases the neurological symptoms are known to persist from weeks to months In a few isolated cases neurological symptoms have persisted for several years and in other cases 250G7 9 recovered patients have experienced recurrence of neurological symptoms months to years after recovery Such relapses are most often associated with changes in dietary habits or with consumption of alcohol There is a low incidence of death resulting from respiratory and cardiovascular failure 8 Target Populations All humans are believed to be susceptible to ciguatera toxins Populations in tropicalsubtropical regions are most likely to be affected because of the frequency of exposure to toxic fishes However the increasing per capita consumption of fishery products coupled with an increase in interregional transportation of seafood products has expanded the geographic range of human poisonings 9 Food Analysis The ciguatera toxins can be recovered from toxic fish through tedious extraction and purification procedures The mouse bioassay is a generally accepted method of establishing toxicity of suspect fish A much simplified EIA method intended to supplant the mouse bioassay for identifying ciguatera toxins is under evaluation 10 Selected Outbreaks O MMWR 4733 1998 This report summarizes an investigation of this outbreak by the Texas Department of Health TDH which indicated that 17 crew members experienced ciguatera fish poisoning resulting from eating a contaminated barracuda O MMWR 4221 1993 Twenty cases of ciguatera fish poisoning from consumption of amberjack were reported to the Florida Department of Health and Rehabilitative Services HRS in August and September 1991 This report summarizes the investigation of these cases by the Florida HRS O MMWR 3516 1986 On October 29 1985 the Epidemiology Division Vermont Department of Health learned of two persons with symptoms consistent with ciguatera fish poisoning Both had eaten barracuda at a local restaurant on October 19 O MMWR 31281982 On March 6 1982 the US Coast Guard in Miami Florida received a request for medical assistance from an Italian freighter located in waters off Freeport Bahamas Numerous crew members were ill with nausea vomiting and muscle weakness and required medical evacuation for hospitalization and treatment The findings were consistent with ciguatera fish poisoning 2 5 0G7 10 TET RODOTOXIN 1 Name of the Organism Tetrodotoxin anhydrotetrodotoxin 4epitetrodotoxin tetrodonic acid 2 Nature of Acute Disease Pufferfish Poisoning Tetradon Poisoning Fugu Poisoning 3 Nature of Disease Fish poisoning from eating members of the order Tetraodontiformes is one of the most violent intoxications from marine species The gonads liver intestines and skin of pufferfish can contain levels of tetrodotoxin sufficient to produce rapid and violent death The esh of many pufferfish may not usually be dangerously toxic Tetrodotoxin has also been isolated from widely differing animal species including the California newt parrotfish frogs of the genus Atelopus the blueringed octopus starfish angelfish and xanthid crabs The metabolic source of tetrodotoxin is uncertain No algal source has been identified and until recently tetrodotoxin was assumed to be a metabolic product of the host However recent reports of the production of tetrodotoxinanhydrotetrodotoxin by several bacterial species including strains of the family Vibrionaceae Pseudomonas sp and Photobacterium phosphoreum point toward a bacterial origin of this family of toxins These are relatively common marine bacteria that are often associated with marine animals If confirmed these findings may have some significance in toxicoses that have been more directly related to these bacterial species 4 Diagnosis of Human Illness The diagnosis of pufferfish poisoning is based on the observed symptomology and recent dietary history 5 Associated Foods Poisonings from tetrodotoxin have been almost exclusively associated with the consumption of pufferfish from waters of the IndoPacific ocean regions Several reported cases of poisonings including fatalities involved pufferfish from the Atlantic Ocean Gulf of Mexico and Gulf of California There have been no confirmed cases of poisoning from the Atlantic pufferfish Spheroides maculatus However in one study extracts from fish of this species were highly toxic in mice The trumpet shell C haronia sauliae has been implicated in food poisonings and evidence suggests that it contains a tetrodotoxin derivative There have been several reported poisonings from mislabelled pufferfish and at least one report of a fatal episode when an individual swallowed a California newt 6 Relative Frequency of Disease From 1974 through 1983 there were 646 reported cases of pufferfish poisoning in Japan with 179 fatalities Estimates as high as 200 cases per year with mortality approaching 50 have been reported Only a few cases have been reported in the United States and outbreaks in countries outside the IndoPacific area are rare 7 Course of Disease and Complications PHR250 41706 7p Other Foodbome Infectious Bacteria Maha Hajmeer This lecture will cover some bacteria only infectious that may be transmitted via food but also water or contact Some microorganisms to be discussed are not conclusively proved to be foodbome The criteria by which pathogens are usually recognized as foodbome were covered in the rst lecture of this course Categories of bacteria to be included this will not be an allinclusive collection Historic 7 agents that were once a major threat via foods in the U S though less signi cant now in the US they may still be important in lessdeveloped countries Sometimes foodbome 7 agents that are occasionally transmitted via foods but represent a greater threat as transmitted by other routes Questioned foodbome pathogens 7 sometimes present in foods not surely pathogenic or pathogenic only in especially susceptible populations Note Although some of these agents are discussed in the 1994 CAST report and other references only Brucella Plesiomonas and Streptococcus Group A are reported to have caused food or waterassociated outbreaks during the most recent reporting periods Bacteria less commonly foodbome than formerly Brucella spp Six species are currently recognized within the genus Brucella Species of concern are B abortus cattle B melitensis and B ovis sheep and goats B suis swine and B cams dogs although rare Although not very common brucellosis Malta fever is a worldwide problem It has been reported in the Americas Europe Asia and Africa The incidence of brucellosis is estimated at lt05 cases per 100000 population in the US with most cases reported from California Florida Texas and Virginia Brucella species cause disease in a number of animals and can also cause infections in humans B melitensis and B suis are more transmissible to people especially via the oral route Brucella species that are of concern to human health are B abortus cattle B suis swine and B melitensis goats and sheep Transmission of Brucella is zoonotic The organism is carried and shed by animals Livestock such as cattle beef and dairy seem to be a primary source of the pathogen at least in the US Some pets eg dogs are also a source Persontoperson contact is not a common route for the spread of the infectious agent Breastfeeding mothers can transmit the infections to infants Similarly sexual transmission has been reported Food vehicles are unpasteurized milk and products made from it of cows sheep or goats Carcasses of infected animals including swine and buffalo are also infectious but do not typically lead to consumer infections Can be transmitted through abrasions of the skin from handling infected animals Incubation range 5 days to 2 months rarely more recurrent prolonged febrile systemic infection If proper treatment is applied to animals infection is cleared within a few days 150E7 2 However some body uids e g blood may be infectious for weeks Reinfection is always a possibility O Hygienic practices are important preventive measures against Brucella Pasteurization will destroy the Brucella therefore it is recommended that individuals avoid drinking unpasteurized milk and eating raw cheese 0 Treatment with antibiotics such as I J 39 m J J 39 J quot t t J 1 plus gentamicin and doxycycline seems to work againstthis pathogen No vaccines are available for humans Live vaccines are used for animals and these may cause disease to humans Corynebacterium diphtheriae O C diphtheriae is the ethiologic agent of a lifethreatening disease known as diphtheria O The first clinical description of diphtheria was provided by Hippocrates in the 43911 century BC 0 In the 173911 century an epidemic swept Europe The disease called the El garatillo or the strangler in Spain and the gullet disease in Italty O The disease reached the American colonies in the 18 11 century and whole families were wiped out 0 Diphtheria in humans is a toxigenic infection usually of the upper respiratory tract The disease is characterized by muscle weakness pharyngitis fever edema or swelling the neck or area surrounding the skin lesion and pseudomembranous material covering the lesions The toxin may eventually reach other target organs via the circulatory system and lead to paralysis and congestive heart failure 0 Treatment is available with antitoxin barring hypersensitivity to horse serum and some antibiotics such as erythromycin or penicillin O The organism also occurs on the skin of infected persons or normal carriers and in wounds and can be spread by droplets or direct contact 0 The role of food in the dissemination of C diphtheriae is uncertain The pathogen has been transmitted by raw milk Milkbome outbreaks were recorded in the US before widespread practice of immunization and pasteurization of milk No foodbome outbreak from C diphtheriae has been reported in recent years in the US Mycobacterium bovis O M ycobacterium bovis causes a contagious and debilitating disease in humans and animals called bovine tuberculosis TB 0 The World Health Organization estimates that 8 million new cases and 3 million deaths are directly attributable to this disease each year Although the occurrence of TB seemedto have decreased in the past quarter of a century recently there is an increase of TB cases worldwide including the US In 2002 California lost its TBfree status after three herds tested positive for the disease 0 Food vehicles are principally unpasteurized cows milk and dairy products made from it The most common means of contracting the disease is through inhalation of aerosols containing the causative agent TB bacteria The bacteria can be exhaled by infected animals and as such individuals in direct or prolonged contact with infected animals are at risk 150E7 3 Weakness or fatigue loss of appetite and loss of weight are some clinical signs ofthe disease Tuberculosis in humans that is caused by M bovis is said to be indistinguishable from that caused by M tuberculosis but since M bovis is most likely to infect consumers via the digestive tract extrapulmonary tuberculosis is more likely Isoniazid is still the drug of choice in most instances but resistance is so common worldwide that WHO recommends treatment with combinations The best way to control bovine tuberculosis is by good sanitation on the farm and in food preparation Bacteria rarely transmitted via foods Clostrz39dz39um d cile O Freeliving sporeforming bacteria found in soils and sediments O The microorganism can contaminate foods but has not specifically been shown to be foodborne 0 Causes diarrhea especially in persons whose intestinal ora has been altered or disturbed such as by the use of antibiotics Altering the ora allows C dz kile to proliferated in the intestinal tract produce toxin and cause watery diarrhea Coxz39ella burnetii Globally distributed and the primary reservoirs are cattle sheep and goats It is common in some companion and wild animals birds and ticks Transmission is most commonly airborne inhalation of dust contaminated with C burnetz39i from dried feces urine or milk or from aerosols in slaughterhouses but the agent is shed in the milk of infected cattle 7 pasteurization of milk is an effective control measure C burnetii causes outbreaks in veterinary and medical centers where large numbers of people are exposedto animals shedding the pathogen About onehalf of individuals infected with C burnetz39i show signs of clinical illness It is also estimated that about 172 of individuals struck with Q fever die of the disease In 1999 Q fever became a notifiable disease in the US Principal sign is fever 7 usually lasts for 172 weeks Other signs and symptoms include headache general malaise chills sweats nausea vomiting abdominal pain Can be treated with tetracyclines or chloramphenicol C burnetii is resistant to drying heat and a number of disinfectants This hardy microorganism can survive for long periods in the environment It an survive pasteurization at 60 C for 30 minutes and can survive for months in dried feces or milk due to the formation of endosporelike structures For this reason the current milk pasteurization timetemperature have been set at 63 C for 30 min or 72 C for 15 s to destroy C burnetz39i M ycobacterium bovis and other milkbome pathogens C burnetii is a highly infectious agent and it is important that effective prevention and control measures be implemented to avoid the risk of infection This includes proper education of practitioners workers or individuals who are at risk of occupational exposure to the pathogen about the hazard sources of infection and necessary precautions appropriate disposal of infected animal materials such as placenta aborted fetuses or fetal 150E7 4 membranes and pasteurization of milk and milk products Streptococcus pyogenes Group A O The genus Streptococcus is classified into Groups A B C D F and G based on a combination of antigenic hemolytic and physiological characteristics Groups A and D can be foodbome and cause illness in humans 0 Group A contains one species with 40 antigenic types 7 S pyogenes 0 Worldwide distribution CDC US 39933997 l outbreak 122 illnesses 0 deaths CAST 52000500000 illnesses 150 deathsyr 540case historically the most common vehicle has been unpasteurized cows milk also Group C pasteurization but any food may be contaminated by an infected handler 0 Causes severe sore throat sometimes scarlet fever rheumatic fever etc treatment usually with penicillin or erythromycin It is estimated that 5 15 of healthy individuals carry this bacterium O Onset of illness occurs in 173 days and the infective dose is low and estimated at lt 1000 cells Associated foods include milk potato salad eggs egg salad and rice pudding 0 Poor hygiene and improper handling of food including improper refrigeration are some factors contributing to problems with Group A Streptococcus Bacteria not conclusively proved to be pathogenic in normal people Aeromonas hydrophz39la O A bacterium that is found in all freshwater environments as well as brackish water 0 Some strains can cause illness in fish and humans 0 Often found in human intestines normal and diarrheal proposed cause of diarrhea in humans especially young children 0 Infection may be acquired through open wounds or ingestion of food or water contaminated with the microorganism Neither causation of diarrheanor transmission via food or water has yet been conclusively proven 0 Associated foods include fish shellfish and red and white meats including beef pork lamb and poultry Enterococcus spp O The genus Enterococcus is the new name for fecal Streptococcus O From the point of clinical microbiology enterococci cause 10 of urinarytract infections and 16 of nosocomial urinarytract infections 0 These have been repeatedly proposed as causes of diarrheal illness in humans but have failed to cause illness in human volunteers transmission via food and water is proposed but unproven Plesz39omonas shigelloides O P shigelloides causes gastroenteritis in humans and the disease agent is suspected to be waterborne 7 the microorganism might be present in unsanitary water used for drinking 150E7 5 recreational purposes or rinsing foods to be eaten raw 0 Found in humans with watery diarrhea causation not proved but two outbreaks have been documented in Japan or with septicemia often accompanied by meningitis It can be isolated from healthy individuals 02732 of the population 0 The rate of occurrence of P shigelloz39des infections in the US is not known Infections with this type of microorganism are rarely reported which may be in part because the disease is selflimiting in nature and people often do not seek medical attention Most reported cases of gastroenteritis involve individuals with preeXisting health problems e g cancer sickle cell anemia 0 Transmission via food and water has been suspected for some time but not conclusively proven 0 Eating contaminated raw shellfish may lead to illness All reported foods involved with cases of gastroenteritis were of aquatic origin salted fish crabs and oysters O The organism can be isolated from a variety of sources including humans birds frsh reptiles and crustaceans O The use of clean water is an important control measure against Plesiomonas gasteroenteritis Also proper cooking of food is recommended to destroy the microorganism Pseudomonas aeruginosa O P aeruginosa is an opportunistic pathogen that is alleged to cause gastroenteritis in humans if ingested in large numbers 0 It is widely distributed in nature and is common in moist environments in hospitals It can be isolated from soil and water and is commonly associated with spoilage of food such as eggs cured meats fish and milk 0 It can colonize healthy humans and can cause disease in people with abnormal host defenses P aeruginosa is pathogenic only when introduced into areas lacking normal defenses such as tissue damage of mucous membranes and skin severe burns intravenous or urinary catheters O Notorious for its resistance to antibiotics 0 Transmission via food and water is proposed but unproven Concept of emerging foodbome pathogens Agents not previously recognized as foodborne Agents in food not previously recognized as pathogenic Problems with Koch s postulates Old agents newly named Summary In addition to emerging foodbome pathogens some seem to be disappearing at least in af uent countries Where zoonoses are concerned some have been significantly reduced by onfarm measures Some agents that occur in foods may threaten only vulnerable populations see table below and some alleged pathogens may be virtually harmless 150E7 6 US subpopulations especially susceptible to foodbome disease adapted from the 1994 CAST report Table 31 p25 Category Number Year Age gt 65 29400000 1989 Pregnant women 5657900 1989 Newborns 4002000 1989 Cancer outpatients 2411000 1986 Nursing home residents 1553000 1986 AIDS patients 135000 1993 Organ transplant patients 110270 19811989 Bibliography Barwick R S D A Levy G F Craun M J Beach and R L Calderon 2000 Surveillance for waterbomedisease outbreaks 7 United States 199771998 Morbid Mortal Wkly Rep 49SS 41735 Chin J D ed 2000 Control of Communicable Diseases Manual 17th ed American Public Health Association Washington DC Claridge JE and CA Spiegel 1995 Corynebacterium and miscellaneous grampositive rods Erysipelothrix and Gardnerella pp 3577378 In P R Murray E J Baron M A Pfaller F C Tenover and R H Yolken eds Manual of Clinical Microbiology 6th ed American Society for Microbiology Press Washington DC Council for Agricultural Science and Technology CAST 1994 Foodbome pathogens risks and consequences Task Force Report No 122 CAST Ames IA Facklam RR and DF Sahm 1995 Enterococcus pp 3087314 In P R Murray E J Baron M A Pfaller F C Tenover and R H Yolken eds Manual of Clinical Microbiology 6th ed American Society for Microbiology Press Washington DC Gilligan PH 1995 Pseudomonas and Burkholderia pp 5097519 In P R Murray E J Baron M A Pfaller F C Tenover and R H Yolken eds Manual of Clinical Microbiology 6th ed American Society for Microbiology Press Washington DC Hajmeer MN and Fung DYC 2006 Other Bacteria Ch 10 In Foodborne infections and intoxications 3rd Ed Riemann H and Oliver DO Eds Academic Press New York NY pp 3417363 Janda JM SL Abbott and AM Camahan 1995 Aeromonas and Plesz39omonas pp 4777482 In P R Murray E J Baron M A Pfaller F C Tenover and R H Yolken eds librio Infections Mehrdad Tajkarimi DVM PhD University of CaliforniaDavis Mehrdad Talkailml DVM PhD PHR39 25 m be pm Genus librio 0 Part of the normal flora in marine habitat 0 Many of them were identified as the most serious pathogens in fish and shellfish marine aquaculture worldwide MehmadTalkavlm DVM PhD PHR39 25 m be pm Genus librio 0 Gramnegative 0 Nonsporeforming bacilli 0 05 08 um diameter 14 26 um long 0 Usually motile by a single polar flagellum 0 Facultative stimulated by NaCl or require it 0 Those of interest in connection with human disease seem to have a natural habitat in brackish water and saltwater Mehrdad Talkailml DVM PhD PHR39 25 m be pm librio parahaemoly cus 0 50 70 of all cases of diarrhea associated with the consumption of fishery products in China 0 25 outbreaks comprising 613 cases 0 deaths in the US 1998 2002 MehmadTalkavlm DVM PhD PHR39 25 m be pm librio parahaemolyticus 0 It is estimated 5122 cases of foodborne vibriosis other than cholera or 1 vun cusinfection in the USyear with 13 deaths CDC Mehrdad Talkailml DVM PhD PHR39 25 m be pm librio parahaemolyticus 0 Pathogenic strains are Kanagawapositive 0 Optimum growth in 2 4 NaCl grows at 8 0 pH 75 86 optimum 0 Temperature gt10 C 420C or 44 C MehmadTalkavlm DVM PhD PHR39 25 m be pm librio parahaemolyticus 0 Infection probably requires ingestion of gt105 cells 0 Incubation 4 30 hr usually 12 24 hr 0 Watery diarrhea with abdominal cramps nausea vomiting fever and headache rarely dysenterylike illness 0 Duration 1 7 days Mehvdad Talkaiimi DVM PhD PHR39 25 n7 uc 0m librio parahaemolyticus 0 Not communicated persontoperson 0 During warm weather occurs in seawater normal flora and seafoods 0 Foods most often associated with human infections are seafoods both shellfish and finfish MehvdadTalkanm DVM PhD PHR39 25 n7 uc 0m librio parahaemolyticus 0 Organism is killed by cooking or by irradiation 0 In China of a total of 83 shellfish samples 38 samples were positive 0 In Mexico more than 1230 cases of gastroenteritis were reported with consumption raw or undercooked shrimp Mehvdad Talkaiimi DVM PhD PHR39 25 n7 uc 0m librio parahaemolyticus 0 Enrichment medium c three incubated over MehvdadTalkanm DVM PhD PHR39 25 n7 uc 0m librio parahaemolyticus 0 V para aemoyl icus colonies are green to blue others are yellow 0 Serologic classification is based on O somatic and K capsular antigens 0 Several problems concerning detection of V parahaemo icusin seafood using culture methods 0 It is recommended to use new techniques such as the PCR method Mehvdad Talkaiimi DVM PhD PHR39 25 n7 uc 0m librio cholerae 0 Causes cholera 0 Waterborne transmission is widespread in the developing world 0 Most outbreaks in the 19th and first half of the 20th centuries occurred in Asia and involved classical V cholerae serogroup 01 causes pandemics MehvdadTalkanm DVM PhD PHR39 25 n7 uc 0m librio cholerae I On the Louisiana and Texas Gulf Coasts in January of 1991 an outbreak due to serogroup 01 biotype El Tor began in Peru and spread through much of Latin America Mahmad Talkanml DVM PhD PHR39 25 7 UC Dans librio cholerae I Grows in the range of 15 C 420C optimum 30 C 370C I pH range for growth is 5 10 Does not require salt but will grow in the prsence o u 6 Serogroups other than 01 and 0139 are fairly widsprad There are also 01 strains that do not produce cholera toxin and therefore do not produce the dismse MahmadTalkanm DVM PhD PHR39 25 7 UC Dans librio cholerae I Infectious dose is personal I Incubation period is a few hours to 5 days usually 2 3 days I Sudden onset of profuse painless watery diarrhea occasional vomiting In untreated cases dehydration may lead to circulatory collapse acidosis hypoglycemia in children renal failure and death Mahmad Talkanml DVM PhD PHR39 25 7 UC Dans librio cholerae I Survivors are immune but not for life to the same M Cheeras type I During 1998 2002 CDC recorded 0 food borne cholera outbreaks in the S and no waterborne cholera outbreaks for the years 2003 2004 I CDC estimates 49 cases of food borne cholera in the USyear wit no deaths MahmadTalkanm DVM PhD PHR39 25 7 UC Dans librio cholerae I Diagnosis in humans isolation of the organism or detection of the toxin eg by ELISA in patients stools I Food samples are enriched in alkaline peptone water at 35 C or 42 C I Detection is by plating on a variety of media some nonselective Mahmad Talkanml DVM PhD PHR39 25 7 UC Dans librio vulni cus I This organism has been recognized first in 1979 I Because of high lethality it is now regarded as an important foodborne disease hazard in the US and possibly in other developed countries I For 1998 2002 CDC reports only one possible outbreak IIbrb othel perhaps because M vun 39cus most often causes individual sporadic cases MahmadTalkanm DVM PhD PHR39 25 7 UC Dans quot 6 1 3 CFUg 39 0 Seawater eastern seacoast Us l I e 4 quotA Vibrio vulni cus my n cLsisanetiologicage t severe human infection wounds 0 n W acquired through ontaminated seafood The strains are divided into mree biotypes e Botype 1 s are pamogemc or umans e otype 2 appear to be virulent for be humans and eels e Botype 3 causing wound infecuons and bacteremia mmadrakanm Mm PHstnm mums Vibrio vulnificus 0 V VuhiI cushas bee detected i coastal and estuarine l 4 environmenls throughout the ff q A world 0 Areas with warm seawater temperatur s Shellfish may constitute one of the most hazardous foods if consumed raw or undercooked Mehmadlillanm M m PHstnm mm Vibrio vulni cus 0 People usually men gt 0 years old chronic i disease chronic alcoholism or immune suppressed ifthey eat raw or underco seafood especially oysters outbreak with high 0 They may become mPr al39ty dramatically in after 12 hours Wlthln one to 3 days week mmmm Mm lawmanquot Mm PHstnm mm PHstnm new Vibrio vulnificus OIn China an Vibrio vulni cus 0 Clams and oysters eastern seacoast Us fairly common among positive oysters average level was 04 when positive had lt10 CFU m mmadrakanm Mm PHstnm mums Vibrio vulnificus 0 Halophilic grows in 6 but not 8 NaCl 0 Fermenls lactose but less frequently sucrose 0 Detection melho ds are similar to those for V parabaemoyticusquot Mehmadlillanm M m PHstnm mm PHR 250 B6 040407 Salmonella spp Mehrdad Tajkarimi 1 Introduction history and contemporary problems 11 Introduction Infections with Salmonella are a major cause of bacterial foodbome diarrhea in humans worldwide These bacterial pathogens are crucial zoonotic agents in the veterinary as well as medical eld Sporadic cases of human infections due to contact with household animals shedding Salmonella have repeatedly been reported however prevalence of Salmonella spp was 0 for all samples from 94 wild turtles 12 History Water and milk were found to be vehicles of the etiologic agent of enteric fever by epidemiological evidence several years before the agent itself was identified in 1874 The organism now named Salmonella enterica serotype Typhi was discovered in 1880 While S Typhi became an enormous problem in the US in the early industrial era the disease burden associated with nontyphoid Salmonella was low before World War II In 1943 in Sweden it was found that 26 of wild rats were carriers of S Enteritidis andor S Typhimurium These creatures still seem closely associated with Salmonella also in the US There are limited historical data on the prevalence of Salmonella in healthy animals carcasses or meat Improvements in sanitation nearly eliminated S Typhi as a cause of indigenous infections in the US and other developed countries Decades later nontyphoid Salmonella infections began to increase in importance 7 a trend that may have peaked near 1990 In 2006 2496 farm samples were collected quarterly from 18 different farms across five states Alabama California North Carolina Tennessee and Washington over a 24 month period Salmonella isolates were recovered from 47 of all samples 13 Contemporary problems Nontyphoid Salmonella infections in humans continue to be a major problem in terms of both morbidity and economic costs Most human Salmonella outbreaks are associated with the consumption of contaminated products of animal origin although nonfoodbome Salmonella infection in humans may be transmitted during contact with animals contaminated water or the environment The widespread distribution of food is a global challenge in Salmonella control With increasing travel and global trade outbreaks involving widely scattered cases are occurring more frequently Recent studies in England Holland and US suggest that for every reported salmonella infection between 38 and 38 persons actually fell ill 14 million infections on non typhoidal Salmonella is the resulting incidence estimate 250B6 2 S Enteritidis in 1995 was the most frequent isolated serotype in 35 countries It may colonize the ovaries of hens and causes vertical transmission to eggs Foodproducing animals are an important source of human nontyphoid Salmonella infection in Vietnam 2 Characteristics of Salmonella Gram negative aerobic or facultative anaerobic motile or nonmotile nonsporeforming rods Catalase positive and oxidase negative Produces acid sometimes and gas from glucose fermentation seldom lactose Reduces nitrate to nitrite Grows readily on very simple media Has 90 DNA homology with E coli Little or no correlation between serotype and clinical signs and symptoms Family Enterobacteriaceae Genus Salmonella Two Species l Salmonella enterica 2 Salmonella bongorz39 Salmonella enterica gt 2400 serotypes Salmonella enterica var typhz39murium 7 now called Salmonella typhz39murz39um or Typhimurium Salmonella enterica var enteritialz39s 7 now called Salmonella enteritidis or Enteritidis Serotyping based on three cellsurface antigens l The O or cellwall somatic antigen 2 The H or agellar antigen and 3 The Vi outer polysaccharide layer antigen 3 Salmonella infection in man and animals Most Salmonella serotypes infect both man and animals and some are hostadapted or hostspecific S Typhz39 7 Man S Pullorum and S Gallinarum 7 Poultry Some have host preferences S Dublin in Cattle The incidence of nontyphoid Salmonella is usually highest in infants and young children and usually the incidence in boysis higher than in girls Most Salmonella infections in the northern hemisphere are around August and in the south around March Comparison of reports of CDC between 1993 and 2003 shows about 100 more fatality in Salmonella outbreaks regardless of 40 decrease in outbreaks Salmonella has a very important role in foodbome diseases i Salmonella is among the most common bacterial causes of foodbome illness ii It is commonly present in many mammal and bird species including all of the meat and poultry product classes produced under federal inspection at frequencies that permit changes to be detected and monitored iii There are methodologies available to recover Salmonella from a variety of meat and poultry products 250B6 3 iv Intervention strategies aimed at reducing contamination of raw products with feces and other sources of Salmonella will likely be effective against other foodborne pathogens Among nontyphoid Salmonella isolates from humans and animal origin from feces carcasses and meat in Vietnam the most prevalent serovar was S Typhimurium 31 Salmonella syndromes There are three different syndromes of Salmonella l Typhoid fever 7 most severe of the three syndromes 0 caused by S Typhi 0 human specific 0 simply human fecal contamination of food or water 0 Fortunately this type of human salmonellosis is just 25 in the US With this syndrome normally the organism is ingested 7 gets to small intestine 7 penetrates epithelial cells of the villi 7 ultimately gets into the lymphatic system 7 phagocytosed by macrophages 7 multiplies within macrophages 7 spills out into blood 7 gets to liver spleen gall bladder and other organs 7 causes systemic infections 2 Enteric fever 7 S Paratyphi A o S paratyphi B renamed S Schottmuelleri o S paratyphi C renamed S Hirshfeldii 3 Gastroenteritis syndrome caused by all other types of Salmonella o gt2400 serotypes ofSalmonella o 150 of them have been associated with human disease 32 Infection in man 7 typhoid fever Systemic febrile illness caused by S Typhi Food and water contaminated with human feces Incubation 1 week to 1 month S Typhi enters body once ingested through M cells of lymphoid tissue in intestinal tract Seldom diarrhea but ulceration of intestine Multiplies in liver and spleen Causes high fever chills convulsions delirium Toxins are not well defined Case fatality rate about 10 May persist in gall bladder for years quotTyphoid Maryquot 7 worked for families house servant rather than in restaurants 33 Infective dose in man and animals 0 Day old chicks l 7 5 cells 0 Four week old 100 71000 250B6 4 Adult hens 10000 or more 50 7 60 lb pigs 10000 or more Infants 100 or less Adult human male 100000 or more Some reject the notion of a minimum infective dose and claim any number of Salmonella can cause infection the probability of which varies with the numbers Issues such as virulence of Salmonella strain individual tolerances and susceptibility and stomach content need to be considered Foods rich in lipids such as chocolate icecream or peanut butter protect Salmonella against stomach acid and it takes only a few cells to produce infection 105 organisms of S Typhi resulted in disease however in an outbreak of S Typhimurium infection from chocolate 10 S Typhimurium per 100 g of chocolate was found 34 Reservoirs A reservoir is the place an organism depends on for its perpetuation The reservoir for salmonellae is the intestinal tract of vertebrates Under the right circumstances it can multiply temporarily in the environment including foods The prevalence of Salmonella in humans in the USA is about 01 The prevalence in animals is generally higher between 0 and 30 35 Transmission Fecal material since the primary reservoir of Salmonella is fecal material The Salmonella infection is acquired by thefecaloral route although swallowing contaminated aerosol may cause infection Raw or undercooked eggs poultry meat and unpasteurized milk cross contamination of other foods during processing and recently uncooked vegetables fruits and direct or indirect contact with animals Persontoperson contacts 7 note that transmission among humans for example via food can not be excluded Some humans as well as animals might be shedders Contact with animals eg pets The Centers for Disease Control and Prevention CDC estimated that about 280000 cases of Salmonella annually were linked to pet turtles 4 Growth and survival of Salmonella 41 Growth Salmonella is not a fastidious microorganism It can grow in simple glucosesalts medium and it can grow more rapidly in highly supplemented media Growth pH values are between 4 and 9 but some can grow at pH of 37 250B6 5 Optimal water activity is between 096 and 0999 The microorganism dies rapidly at 07 7 08 and more slowly at lower values Oxidationreduction OR potential This has little effect on growth or survival of microorganism The growth temperature range of this microorganism is between 5 7 45 C with an optimum growth temperature of 35 7 37 C 42 Survival Salmonella can be killed by repeated freezing and thawing cycles of food but this might have an adverse effect of food quality Heating can kill Salmonella Some strains are more resistant to heat than others For example S senftenberg 775W is 10 7 20 times more resistant to heat than an average strain of Salmonella but it is rare At 60 C the decimal reduction time D value is between 04 and 06 min One D value equals 90 kill Two D values equal 99 kill and so on The zvalue change in temp needed to change D value by a factor of 10 is 4 7 5 C Thus D value at 55 C is 4 7 6 min Salmonella is more heatresistant in egg yolk than in white Also it is highly heatresistant in dry foods and foods rich in fat In milk chocolate with less than 2 moisture the D value is 222 min 37 h at 80 C 43 Competition against other microorganisms Salmonella has short lag phase and can grow rapidly Intestinal ora of adult hens is inhibitory competitive exclusion Five percent 5 of Salmonella strains produce bacteriocins against E COll Shigella or Salmonella 44 Detection of Salmonella Nonselective preenrichment to repair cell damage rehydration and dilution of toxic substances lactose broth buffered peptone etc Selective enrichment to inhibit other bacteria Tetrathionate Selenite cystine RappaportVasiliadis Malachite green Differential selective agar media to select and identify Salmonella brilliant green novobiocin XLT4 bismuth sulfite Biochemical confirmation Serology Rapid Methods Immunoassay Gene probes PCR and electrical measurements conductance 250B6 6 5 Control of Salmonella in food and feed 51 Poultry products 511 Pre harvest control Poultry products could be contaminated at several stages during slaughter evisceration cutting defeathering cross contamination on surfaces chilling in a water bath reduces the load of Salmonella However this may enable cross contamination from contaminated t0 uncontaminated products Correlation between levels of Salmonella in broiler ocks and carcasses after slaughter has been documented in some studies Prevention of bird ock contamination based on the Good Manufacturing Practices and Good Agricultural Practices in addition to vaccination control of feed stuff contamination are most useful ways to prevent contamination of bird ocks before slaughter 512 Post harvest control Control of scalding temperature between 50 C and 60 C with countercurrent or spray scalding Control of defeathering evisceration system hygiene Improvement of rinse chill system 52 Shell eggs 521 Pre harvest control Culling of infected birds and with Salmonellafree birds note in the birds we can not see clinical signs of salmonellosis as in humans Vaccination Management control 522 Post harvest control Heat Irradiation Whole egg pasteurization in 600 C for 35 minutesiexpensive Irradiation 3 kGy 53 Pigs In a recent study in US samples were collected on farms feces and at slaughter distal colonic content cecal content and ileocolic lymph nodes The mean individual pig prevalence was 5 for feces 4 for distal colonic content 15 for ileocolic lymph nodes and 17 for cecal contents Serological surveillance of pig herds and slaughter of animals based on the serological surveillance result would be the recommended pre harvest and post harvest control in this regard 54 Cattle beef and dairy products 250B6 7 Serological surveillance of cattle establishing Salmonellafree herds control and management of surface water and pastures after application of manure slurry or sludge effective rodent control program control and prevention of wet areas personnel hygiene would be the recommended pre harvest controls in this regard Milk pasteurization and sufficient cooking temperature of beef would be the post harvest recommendations In a study in Turkey Tulum cheese produced from raw milk Salmonella was found in 24 of samples 55 New food vehicles Contamination of new food vehicles typically occurs early in the production process These foods have fewer barriers to microbial growth Salmonella presence in fresh fruits and vegetables were investigated in a study by CDC Contamination may occur during production and harvest initial processing and packaging distribution and final processing Contaminated water seems a particular source of the contamination and chlorination of water could be a critical issue in this regard 56 Feed In one study in the Netherlands 10 of poultry feeds and feed components were contaminated with Salmonella and in another study in the US 28 of feed and feed ingredients and 467 of farms were contaminated with Salmonella Pelleting temperature 82 C for 15 second and Good Agricultural Practices would be effective ways to control salmonellosis in animal feed Large outbreaks of canine salmonellosis occunred in military watch dogs due to Salmonella Montevideo andor Salmonella Give This demonstrates not only that those Salmonella infections in dogs occur without clinical symptoms but also that large outbreaks occur after feeding dehydrated dog foods Selected references Bahnson PB FedorkaCray PJ Ladely SR and MateusPinilla NE 2006 Herd level risk factors for Salmonella enterica subsp enterica in US market pigs Preventive Veterinary Medicine 76 2497262 Bryan FL Fanelli MJ and Riemann H 1979 Salmonella infections pp 73130 In H Riemann and FL Bryan eds 1979 Foodbome Infections and Intoxications 2d ed Academic Press New York Colak H Hampikyan H Bingol E B and Ulusoy B 2007 Prevalence ofL monocytogenes and Salmonella spp in Tulum cheese Food Control 185767579 Gray JT and FedorkaCray P 2002 Salmonella pp 5568 In Foodbome Diseases 2nd Ed Cliver DO and Riemann H Eds Academic Press New York PHR250 5806 6p Poisonous Plants and Residues Michael E Mount POISONOUS PLANTS 1 Cassava and Bitter Almond A perennial woody shrub that is grown as a root crop in the tropics and considered the fourth most important source of calories for humans among crops produced in those areas It is an important staple for about 800 million people worldwide About 120 million tons of cassava produced annually worldwide as measured from 1979 to 1981 9 Africa produces 37 of the world cassava crop and contains over 50 of the earth39s soil used for cassava growth world cassava area 9 Asia produces 37 of the world crop and accounts for 27 of the world cassava area India Thailand and Indonesia are major producers 9 Brazil dominates the production of cassava in the Western Hemisphere approximating 20 of world crop Colombia and Paraguay are also major producers O Papua New Guinea and Fiji are important producers in the Paci c Cassava is considered an important basic energy source for the human diet that can be produced on marginal agricultural lands It has become an important food source in addressing growing food de cits especially in povertystricken areas in third world countries The plant is used as animal feed and for industrial uses of starch Sometimes cassava is considered as undesirable food that contains little besides carbohydrate However in many developing countries calories are the paramount nutritional shortage The cyanide present in cassava is a drawback Chronic cyanide toxicity occurs only in certain areas of Africa and it appears to be associated with severely de cient diets combined with an underprocessing of cassava for food preparation Cassava Manihot esculenta Crantz is in the spurge family Euphorbiaceae It originated in South and Central America between the 30 N and 30 S latitude Two distinct types of cassava exist the sweet and the bitter 150K6 2 Commercially cassava is grown by planting a cutting taken from the woody part of the stem It grows well in low fertility soils and can tolerate long periods of drought The roots begin to develop into starch storage bins at about three months of age The plant can be harvested anytime after that or can be grown for 2 3 years before harvest The plant is not harmed by locust swarms since the root is not damaged and provides nutrients for re growth of the vegetative parts Raw cassava contains two cyanogenic glycosides linamarin and lotaustralin which can release prussic acid hydrogen cyanide HCN Generally the cyanogenic glycosides are not considered toxic Once ingested by a person the following reactions occur Linamarin gt Glycoside Cyanohydrin gt HCN The HCN is the toxic form of cyanide It targets the ferric iron Fe3 of the quotaquot cytochromes of the electron transport system in the mitochondria As a result electron transport to oxygen is inhibited and energy production stops no ATP being produced resulting in rapid cell death The body is able to detoxify low levels of cyanide in the body through the action of an enzyme rhodenase by the following reaction HCN sulfur gt SCN thiocyanate This is an important reaction since the formation of thiocyanate contributes to the chronic toxicity problems of cyanide It is excreted by the kidney Health problems can result from cassava ingestion Acute death has occurred from eating raw roots due to high levels of cyanide Death is due to the lack of energy production in the brain and heart Proper processing of the plant by drying soaking in water or cooking reduces the cyanide levels so that the roots are not acutely toxic Chronic cyanide toxicity occurs within some localities in Africa Areas of high cassava consumption low meat diets and low iodine intake lead to the development of a two syndromes known as tropical ataxic neuropathy and epidemic spastic paraparesis The incidence is as high as 3 in some areas Tropical ataxia neuropathy is associated with damage to one specific spinal cord tract that results in difficulty walking due to ataxia muscular incoordination when voluntary muscular movements are attempted It occurred with high incidence in adult males from Nigeria Epidemic spastic paraparesis is an acute disease mostly in women and children causing permanent crippling of victims from one day to the next by damaging nerve 150K6 3 tracts in the spinal cord necessary for movement resulting in a spastic paresis partial or incomplete paralysis with tense muscles of both legs A period of food shortages in the 1980 s affected 10000 women and children in cassavadominated areas Families consumed new crops without proper processing due to starvation The conditions are permanent High cassava ingestion and low dietary protein are associated with these neurological disorders Additionally the body39s pool of sulfur is lowered when cyanide is ingested at low levels due to the formation of thiocyanate SCN that is excreted from the body via the kidney Thus sulfur containing aminoacids in the body become deficient This deficiency may play a role in development of the syndromes Also the enzyme thiocyanate oxidase can convert thiocyanate to free cyanide that may affect neuronal cells Experimental studies have demonstrated that cyanide can induce demyelination of nervous tissue The exact mechanism of how this occurs in not well understood Another plant that causes spastic paraparesis similar to cassava is Lathyms sativa This is also an important plant in areas of the world similar to cassava It serves as a dietary staple in areas of drought It contains lathrogens that are toxic amino acids and cyanoalanine a nitrile Consumption of seeds peas is the source of poisoning Goiter and goiter cretinism are other problems associated with cassava Goiter is due to iodine deficiency resulting in enlargement of the thyroid gland In areas where the dietary iodine is marginal cassava consumption leads to an increase in the incidence of goiter in man and animals The high production of thiocyanate by the body due to continual ingestion of cassava results in interference with iodine uptake by the thyroid gland The resulting effect is iodine deficiency that leads to the development of goiter Goiter cretinism is an endocrine disorder involving the thyroid and the central nervous system Neurological cretinism is associated with mental deficiency hearing and speech problems disorders of stance and gait and stunted growth Myxedematous cretinism has the same signs plus problems associated with hypofunction of the anterior pituitary gland There are 2 hormones released by the thyroid gland T4 and T3 Individuals with this disease have very low thyroid hormone T4 but paradoxically have elevated T3 levels This is thought to possibly be responsible for the neurological damage associated with cretinism that leads to myxedematous and neurological cretinism Newborn children are affected with myxedematous cretinism at 2 7 in some African communities This is a very rare disease condition Congenital hypothyroidism in Africa is 15 of newborns 150K6 4 500 times the rate of industrialized nations Thiocyanate elevated in individuals is believed to prevent the secretion of iodine from the mother to the developing child in utero Similarly it prevents the secretion of iodine into the milk of nursing mothers that continues the disease process Again the exact mechanism of goitercretinism is not well understood A commercial woody tree that is grown for oil extraction of its fruit Amygdalus communis var amara is commonly known as Bitter Almond It is wellknown in Europe The fruit almond of this plant contains amygdalin a cyanogenic glycoside containing benzealdehyde When cyanide is formed benzealdehyde is released producing a characteristic odor referred to as the bitter almond smell These fruits are grown for oil extraction of essential oils that are used in the perfume industry as well as in health foods Raw fruit is added to specialized recipes to provide the bitter taste characteristic of these nuts Ingestion of too much raw fruit can produce acute cyanide poisoning Similarly the remaining cake residue of bitter almond following extraction for oil contains amygdalin that will produce fatal poisoning when fed to livestock This is not to be confused with Amygdalus communis var dulcis which is the Sweet Almond This almond is the confectionary nut common throughout the world and regarded as a good health food It also contains essential oils that can be extracted for purposes similar to bitter almond This nut does not contain any cyanogenic glycosides and the entire plant is considered safe The almonds grown in California are from this plant Water Hemlock Cicuta douglasii and C maculata Western waterhemlock and Spotted waterhemlock respectively are two plants of concern in California belonging to the Parsley Family UmbelliferaeApiaceae The plants are perennial herbs The leaves are twicecompound and the segments are not divided The roots are tuberous and show a series of crosspartitions containing the yellow liquid The owers are white and in large open compound umbels The seeds are at faced to concave There are seven species of Cicuta in the US The whole plant is toxic but especially the root that contains a readily visible yellow liquid Leaves are also very toxic early in the spring 150K6 5 All domestic and wild animals are susceptible Man is susceptible because of mistaken identi cation of the plant for edible parsnip plants Lomatium sp Sium suave Western waterhemlock is found in northern and central California being able to grow at elevations to as high as 8000 ft Spotted hemlock is found in central and southern California and also in Modoc county of California In addition this plant and its varieties are spread across the US These plants are associated with fresh water streams ditches and marshes and are the most poisonous plants in the Northern Hemisphere These plants contain an unsaturated longchain aliphatic alcohol called cicutoxin a neuropoison Clinical signs include nausea salivation and emesis that can develop within 15 60 minutes of ingestion Trismus tetanic spasm of the jaw muscle and toxicclonic convulsions occur shortly thereafter leading to unconsciousness cardiac arrest and peracute death Diagnosis is by the history of eating naturally growing plants in the Umbelliferae family Plant identification and chemical analysis of body uids for cicutoxin will con rm the diagnosis Treatment for the condition is invariably futile Removal of the poison with gastric lavage and activated charcoal oxygenassisted ventilation pentobarbital epinephrine atropine sodium bicarbonate and body warming are commonly attempted Poison Hemlock Conium maculatum Spotted Hemlock is a common weed in California and other states There are two species ofpoison hemlock in the US These plants like waterhemlock are in the Umbelliferae family Poison hemlock is a tall branching biennial herb sometimes attaining 10 ft high It has a long white often branched tap root The stem is stout smooth and dotted with irregular purple marks The herbage has a mouselike odor The leaves are twice compound and the segments are toothed or deeply cut The petiole is often purple colored The owers are white and in large open compound umbels Fruits are oval granular and have prominent wavy ribs with the face grooved The plant is mistaken for wild carrot Daucus carota by persons who desire to quotlive offthe landquot 150K6 6 The roots and seeds are the most toxic but all parts of the plant are poisonous since the poison accumulates with age in the seeds roots stems and leaves The degree of toxicity varies Several alkaloids are found in this plant and their content uctuates The major toxic principle is coniine and related alkaloids One of the related alkaloids Bconiceine is 7 8 times more toxic and is present in higher concentrations during the growing season when fruits are green Coniine is volatile and is slowly lost on drying Exposure to pregnant animals causes congential malformations particularly in cattle and pigs Other animals can be affected too In man a woman with child would have in ingest the plant for several days to weeks at a dose not producing acute signs Both coniine and Bconiceine are responsible The malformations are related to decreased movement of the fetus at specific critical times of development Poison hemlock has historic interest It was used as a lethal agent during that time of history It is plant that Socrates was forced to drink and whose course of poisoning was recorded via Socrates himself The clinical signs of acute poisoning are that of ascending paralysis They develop in progressing order including nervousness trembling ataxia of rear legs mydriasis collapse bradycardia poor perfusion coma and respiratory failure leading to death A convulsive syndrome may occur particularly if ingestion of the roots or seeds occurs Identification of the plant and the history of eating naturally growing plants in the Umbelliferae family will make diagnosis possible A mousey odor is helpful in identifying the plant Analysis of stomach contents or body uids for the alkaloids can be performed if no history is available Proper removal of the plant during acute poisoning often results in an uneventfully recovery within several days but the prognosis is guarded Supportive care is important in moderately affected persons while ventilatory assistance is required for comatous individuals Death can occur Death Camas Zigadenus sp Death Camasis a member of the lily family Liliaceae These plants are herbaceous perennial plants with onionlike bulbs lacking the onion odor and slender folded linear leaves A single showey flowering raceme characterizes the plant with yellowishwhite colors The plants sprout very early in the spring 150K6 7 The whole plant is toxic including the owers but the bulbs are most toxic The toxic principle are alkaloids called zygacine and zygademine iso and neogermidine and protoveratridine Both cattle and sheep are susceptible to poisoning under grazing conditions One bulb can kill a sheep Man is poisoned by mistakenly eating the bulbs of the plant that was believed to be an onion plant Clinical signs are primarily that of vomiting nausea and abdominal pain within one hour of ingestion The heart rate characteristically slows down so that bradycardia is present Generally more serious signs do not develop in adults The onset of severe illness may occur in children with the development of weakness staggering hypotension and dyspnea troubled breathing Collapse coma andor seizures may develop Identi cation of the plant and the history of eating naturally growing plants in the Lily family will make diagnosis possible Urine and stomach contents can be submitted for an alkaloid screen Antiemetics are recommended for treatment of adults plus oral administration of activated charcoal Treatment is aimed at correction of hypotension with uids and vasopressors and with atropine to correct bradycardia in patients with more advanced signs More serious signs would require arti cial ventilation and drugs to control seizures Patients respond favorably DRUG RESIDUES De nition The concentrations of drugs or environmental chemicals that are detectable by analytical methods are de ned as drug or chemical residues in tissues of food producing animals and other agricultural commodities for human consumption Residues refer to the parent drugs or chemicals their metabolites and their decomposition products if formed The quantity of residue if detected is expressed by weight such as a mg of drug present in a kg of tissue which is parts per million ppm If expressed as ug of drug present in a kg of tissue then it is parts per billion ppb Fluids such as milk are expressed in lliter units instead of a kg Residues are either intentional or unintentional Intentional residues result from a desired usage of the drug in animals or food products Unintentional residues are caused by events that exposed animals or food products to drugs or chemicals not intended to be received by them 150K6 8 Importance Federal law governs the amounts of residues allowed in human foods The Delaney Amendment of the Food Drug and Cosmetic Act states that a known carcinogen is illegal in foods consumed by man This is referred to as quotZero Tolerancequot and infers that no residue of a carcinogen is allowed for edible foods Analytical sensitivity determines the quotZero Tolerancequot However absurdity in certain cases has allowed exceptions to be applied to this Amendment Drugs and chemicals that do have a nite quotTolerance Levelquot are allowable in foods as long as the quantity is within an established quotMargin of Safetyquot A quotTolerance Levelquot is established which allows residues to be acceptable for sale that are equal to or below the tolerance limit Residues that exceed the quotTolerance Levelquot are illegal and not saleable for human food The largest source of drugs that can result in residues is the foodproducing animals Over 300 feed additives and antimicrobial agents are in use within the US for applications in livestock and poultry New drugs are being added annually Feed additives are drug chemical or biological substances added directly to animal feeds in small quantities for the purpose of increasing performance or production Antimicrobial agents are drugs used to treat infectious diseases or other pathogenic agents that produce disease Indiscriminate use of drugs is the cause of drug residues Proper management of animals and following directions on drug usage will avoid residue problems in most cases Agencies Associated with Residues In the US four entities interact in the control of drug or chemical residues Food and Drug Administration FDAl This is a federal organization that regulates the safety of drugs used in the United States The agency is responsible for setting quotTolerance Limitsquot of drugs and enforcing violations of quotTolerance Limitsquot established for milk United States Department of Agriculture USDAl This is a federal organization that is responsible to enforce violations of quotTolerance Limitsquot set by FDA for drugs or for chemicals which are set by EPA in meat or poultry products 39 Protection Agencv EPA This is a federal organization that determines the safety of chemicals used within the environment They are responsible for setting quotTolerance Limitsquot of chemicals used in the environment such 150K6 9 as various pesticides fungicides or industrial contaminants They also enforce violations of these quotTolerance Limitsquot 0 Drug Companies These are privately owned enterprises Every drug or chemical that comes upon the market must go through an extremely laborious study in order to determine its toxicological properties and its safe application in man animals or other agricultural commodities Every drug must be quali ed for review by the FDA by application from the drug company for a quotNew Drug Applicationquot which entails proof performed by the drug company of the drug s toxic effects efficacy and safety Establishment of Tolerances o Tolerances are determined for noncarcinogenic compounds drugs or chemicals which do not induce cancer by using the no effect drug concentration in the most sensitive species used for study Several factors are then applied to calculate the tolerance of drug based upon studies performed by drug companies and upon human biological estimates 0 The quotAcceptable Daily Intake ADIquot is the daily dose of a drug or chemical residue that a human would be exposed to throughout their lifetime so that no appreciable health risk would exist The ADI is established to provide the estimate of the maximum quantity of which can be safely eaten in food without health risk concerns Feeding trials in animals primarily are the basis for determining the ADI s In order to determine the ADI a no effect level of the drug must be determined It is determined by feeding trials in various laboratory rodents conducted over a 2year period Sixmonth or longer studies are performed in nonrodent species such as the dog or monkey The species for which the drug is intended target species must also be studied The maximum dose fed that produced no harmful adverse effects in the most sensitive species is de ned as the noeffect level or noadverseeffect level Based then upon the body weight of the most sensitive species and the dosage of drug eaten per day a quotmg of drugkg of body weightquot is defined Then this quotmgkgquot amount is divided by 100 safety factor to give the ADI for that drug The formula for 200 g rats that eat 15 gday and have a noeffect feed level of 100 ppm would have the following calculations 15 g1000 gkg x 100 mgkg ADI 75 mgkg 02 kg rat 150K6 10 Add safety factor 75 mgkg 100 75 x 102 The tolerance level can now be calculated by using the ADI and a food factor constant Consumption factors are based upon consumption of muscle being 033 of the total diet The factor for muscle in all species beef pork lamb poultry is one This indicates that it is the most consumed and consisting of 033 of the total daily diet Other organs such as liver kidney skin and fat have higher whole numbers two to five depending upon which species The higher the number the less this tissue is eaten relative to muscle since 033 is multiplied by the number The formula to calculate tolerance is given below ADI mgkgday x 60 kg Tolerance Food Factor x 15 kgday Sixty kg is the average human adult body weight Man is estimated to consume 15 kg of foodday The food factor is one for beef muscle If the ADI of a noncarcinogenic drug in beef muscle is determined to be 825 X 10394 the tolerance would be as follows 825x10394 x 60 T 01 mgkg which is 01 ppm 033x1 x 15 Hence the tolerance set for the drug in beef muscle would be 01 ppm Carcinogenic Mutagenic and Teratogenic Drugs 0 Carcinogenic drugs or chemicals are initiators or promoters of cancer These drugs bind irreversibly with DNA proteins and other cellular components to form adducts Adducts are damaged cellular machinery It is estimated that 1x105 adducts can be removedcell 12 hr by DNA repair systems which implies accumulation may not occur as rapidly However there are many natural and environmental carcinogens which also invade the body that add to the adduct load The goal then is to minimize this adduct load 0 Drugs are tested for carcinogenicity and those found to be so are eliminated from development since no carcinogenic compounds are to be present in human foods A atoxin is an exception It is an unintentional carcinogen that does have a tolerance limit in peanuts 20 ppb and milk 05 ppb 150K6 ll 0 Mutagenic drugs or chemicals damage the genetic engineering of a cell or organism Basically damage occurs to DNA by point mutation gene elimination or chromosomal breakage Evaluation of mutagenic effects by drug companies is performed by threegeneration reproductive studies in various species and other specialized tests A natural mutagen believed responsible for colon cancer is S 3 l357 J J J 39 y l r J J39 39 which is produced in the bowel of humans by ve species of bacteria Teratogenic drugs or chemicals produce damage to the developing embryo or fetus during a critical phase of gestation pregnancy Congenital malformations affect the structure and bodily functions of the animal tested An excellent example of this was the tragic results from the thalidomide incident that occurred in Europe It was used to control morning sickness in pregnant women Several years after its usage it was found responsible for inducing phocomelia seal limbs in children The FDA did not allow thalidomide to be used in the US because they were not convinced by the data provided by the drug company that it was safe That is a real tribute to the FDA Drug companies must perform the threegeneration reproductive studies in various species along with other specialized tests to demonstrate if the drug is teratogenic or not Finite tolerances can be made for mutagenic and teratogenic compounds but the safety factor used in determining the ADI is 1000 When the tolerance is calculated it will be 10fold lower than a noncarcinogenic drug s finite tolerance which is not mutagenic or teratogenic Margin of Safety The above calculations are providing a quotMargin of Safetyquot for all drugs To do this at least two species require lifetime or chronic toxicity testing One species must be a non rodent Once the ADI is calculated the safety factor is incorporated If the ADI is run in the target species only a safety factor of 10 is required Interspecies ADIs require another 10 factor resulting in 10 x 10 100 as the safety factor Drugs known to be mutagenic or teratogenic have a safety factor of 1000 The average daily intake of the drug by the species studied is then divided by the safety factor Withdrawal Times Withdrawal time is the time required for the drug to reach a safe concentration as determined by tolerance As a result a time interval is established from the time of drug removal to the time of slaughter that allows for the drug to deplete from the body in order 150K6 12 to be within tolerance In 1958 the Food Additives Amendment made it mandatory for drug manufacturers to submit tissue residue and depletion data along with methodology to detect the residues This amendment involves drugs used for food producing animals only The depletion data are extremely important since the FDA determines the tolerances Therefore calculation of the time interval can be made based upon such data The halflife of the drug is determined in these instances The residue amount in the tissues of study will decrease at each successive measurement The drug amounts are plotted against the time of measurement following drug removal When plotted on a semilog graph a relatively straight line results Using this the halflife of the drug can be determined Calculation of the halflife will then allow the withdrawal time to be established since the time at which the tolerance limit is passed can be realized Each tissue in the body has differing depletion rates of the drug which means the halflife is different between tissues Some Drugs and Chemicals Assayed for Residues in Edible Foods Antibiotics These are antimicrobial agents of various types They are used primarily for treatment of acute disease but some are used prophyllactically preventatively and fed for long periods of time Measurement of residues is to prevent antibody resistance in microorganisms due to outofcontrol residue levels being found in foods protect against hypersensitivity allergies and avoidance of potential chronic diseases induced by certain antibiotics such as chloramphenicol a Tetracyclines Fquot Chloramphenicol Penicillin and related drugs oo Dihydrostreptomycin Novobiocin Neomycin Gentamycin Cefoperazone cephalosporin3rd generation Hwtmwrv Sulfonamides Environmental Chemicals a Polychlorinated Biphenyls e Dioxins b Hexachlorobenzene f Pentchloronitrobenzene OTHER FOODBORNE Categories oHistoric foodborne ents oSometimes foodborne oQuestioned foodborne pathogens Species of concern a 39 oB abortus cattle oB melitensis amp B ovis sh p amp goats oB suis swine and 0B canis dogs although rare OTHER FOODBORNE NFECTIOUS BACTERIA oSorne are not c clu 39Vely proved to be foo orne criteria for foodb rne Historic foo oBrucella spp oCorynebacterium diphth oMycobacterium bovis Brucella oBrucellosis Malta er is a worldwide problem olncidence of brucellosis in e 7 lt05 cases per 100000 iMost reported from Californi Florida Texas and Virginia Brucella Transmission of Bru la is usually zoonotic The organis 39 carried and shed by animals oLivestock such as cattle bee an dairy are a primary source of e pathogen at least in the US oSome pets eg dogs also a source Brucella Olncubation period 1 ORecurrent prolonged systemic infection ORecurrences are common an may be accompanied by arthrit39 OAntibiotic treatment 2 Coryne erium diphtheriae oDiphtheria rst clinic Hippocrates in the 4 11 cen oAn epidemic swept Europe in century Called El garatillo t e strangler in Spain amp the gullet disease in Italy oReached American colonies in the l 1 centuryiwhole families wiped out described by BC Food vehicles oUnpasteurized milk c sheep or goats and mi products oCarcasses of infected animal including swine and buffalo don t typically lead to consume infections Brucella milk and eating rawmi ONo vaccines available for humans OLive vaccines available for animals may cause disease in humans infection usually of upp respiratory tract oLifethreatening oControlled by vaccination of humans no animal hosts c diphthe 39 pasteurization of milk mach e milking oNo foodborne outbreak reported in recent years in the US aerosols containing the agen o Tuberculosis caused byM bov indistinguishable from M tuberculosis infects consumers vi the digestive tract gt extrapulmona tuberculosis more likely pathogens are M bovis bumelii oThe heat resistance of M 0 39s provided the basis for the conditions of hightemperature shorttime pasteurization 72 C 15s of milk and animals called bovine tuberculosis TB oWHO 8 million new cases an 3 million deaths each year milk and its products oln 2002 California lost its status after three herds tested positive for the disease Bacteria rare foodborne oClostridium dif cile oCoxiella burnetii oStreptococcus pyogenes BaCteria ely f db me Bacteria ly foodborne Clostridz39um dz i39cz39le Coxiella bumem o Freeliving in soil amp sedi ts Globally distributed 0 Can contaminate foods but n t speci cally shown to be foodb Causes Qfever oPrimary reservoirs sheep ca e 0 Causes diarrhea after antibiotics altering ora allows C dz39 z39cz39le to goats companion amp Wild grow in intestinal tract produce animals birds ticks toxin amp cause watery diarrhea Coxiella bu 0C bumetii is a highly 39 agent oResistant to drying heat an a number of disinfectants olt can survive for long periods 39 the environment animals especially at pa ri 39 n oCan be shed in milk of infec 1 animals basis for low temperature longtime pasteurization Streptm us pyogenes Streptoc us pyogenes Group A OMOSt common veh e IS raw oGroups B C D F and oBased on a combination of 39 enic salad eggs egg salad hemolytic and physiological 39 pudding may be contamin ed OGroups A and D can be foodbo e amp by infected handler Cause human illness olnfective dose is low est lt10 0 oGroup A one species S pyogene cells with 40 antigenic types Streptococc oCDC US 98 02 1 4 cases 0 deaths oCAST 52000500000 case 150 deathsyr 540case Questions foodborne pathoge erromonas hydrophz39la oEnterococcus spp oPlesiomonas shigelloz39des oPseudomonas aerugz nosa Aeromonas Some strains can cause illness in fi humans Often found in human intestines norma diarrheal proposed cause of diarrhea in h ans especially young children via food or water have not yet be n conclusively proven o Suspected food vehicles sh shell sh and meats including beef pork lamb and poultry name for fecal Streptoco oEXperiments have failed to illness in human volunteers oTransmission via food and wate is proposed but unproven Japan or with septicemia ofte accompanied by meningitis oMost reported cases of gastroenteritis involve people preeXisting health problems e g cancer sicklecell anemia Plesiomo shigelloides o Suspected to be wate ome 7 disease purposes or rinsing foods to b e raw oEating contaminated raw shell sh may lead to illness All reported foods involved with cases of gastroenteritis were of aquatic ori in salted fish crabs and oysters normal defenses such as t1 damage of mucous membra skin severe burns intravenou or urinary catheters oTransmission via food and water 39s proposed but unproven countries oOnfarm measures vs zoon e oSome agents that occur in foo s may threaten only quotvulnerable populations oSome alleged pathogens may be virtually harmless Pseudo as aeruginosa humans if ingested in larg numbers oCan be isolated from soil and water and is commonly associat d with spoilage of food such as eg s cured meats sh and milk oAgents not previously as foodbome oAgents in food not previous recognized as pathogenic oProblems with Koch s postulate o Oldquot agents newly named At risk oAgegt 65 0 Pregnant women o Newborns 0 Cancer outpatienm 0 Nursing home residents 0 AIDS patients 0 Organ transplant patienm FOODBORNE PARASITES PHR 250 Foodborne Infections and lntoxications OVERVIEW Some of the parasites transmitted via food amp water mostly from North America microscopic o Reproduce sexually some are hermaphrodites Macroscopic transmitted as rm Life cycles in gtl host species httpWWW dpdcdcgoVdpdx FOODBORNE PARASITE GROUPS Roundworms Tapeworms Flukes FOODBORNE ROUNDWORMS Trichinella spiralix Asclm39x lumbn39coides Anisakid s Anisakix w39nylex herringworm whaleworm Pseudoterranova decipiens codwurm sealworm T richinella spiralis Trichinosis potentially fatal Larval cysm in muscles of swine other carnivores bears Mate in intestine ovovivipary larvae via lymph amp blood to muscles encystation Prevention thorough cooking or reezing or irradiation of meat V mgmun 01 Newquot quot39 undelcuaxed max mem smst m pm mm m m suiaied muscle A a Larva mused m small imam T richinella life cycle in mm In slriglyed muscle a 1 mmquot omum mum Amman9 mm m AD4aannsucsmge 0 magi T uscle Section quotE s iralis Larvae in Ascaris lumbricoides Large roundworms 7 intestinal obstruction Transmitted by eggs in human feces under favorable conditions eggs mature after 2 3 weeks may remain Viable in soil or sewage sludge for years A mm mg A Dizwnusnc slag 0 Ascaris lumbricaides life cycle I FemluedgggA Oumumm A wm not un zmu biwbgwul welnpmenl Ascariasis in a child Ad ult Ascuris lumbricaides Swine Ascarias s Ascaris eggs Buyb39xman39x larva emerging from egg follawing 4 months in formalin Anisakids principal species Anisakis simplex Pseudoterranova decipiens Larvae from raw marine sh sushi ceviche etc sometimes invasive Prevention by cooking sh thoroughly or freezing Anisakid life cycles Anisakis de nitive hosts are cetacea eg dolphins porpoises Whaleworms Pseudoterranova de nitive hosts are pinnipeds seals walruses sealworms mm W mm mm m m o mmmmmm m ummnm m m mm W WWW wmmm mm mm lt Mum g WWW I 3 k x x k 74 a g A 2 3 x A 7w j l f 1x 1 owisk imz39mmzzm o mm lawn mum in m 7nqu 5 mm mm Madman the um um mnmm m run in w Wham 0 may m A mm mu m 0 mm m 3 Al smw Shea Mama my Mm mm m b m bygasumwzamwmm ammg m1 m m Wm mm A vim hm usun nmammq La law1e an mm 6 by mum mammal mu mm mm lvma m 1mg mm mm Mm Am wnlvm mama essunm am am Iymmme mnmmnl o 7 H V mmemmmnmua umllvhvwnlmwns V gt 74 V V A 4 397 4 mim fm m A w Anisakid life cycles 9m mm mamam A 1 u Wynn m mama v humans w mnrme mm Anisakid in sh llet FOODBORN E TAPEWORMS Taenia saginata beef tapeworm Taenia solium pork tapeworm Diphyllobothrium latum sh tapeworm T aenia life cycle Aswan develog min nyslmaru m mu camzw mgmmmand wqu mm hecume mth m memo mummy wmzmmmed by eggs I mum mm A mama sage Amwmsm T aenia saginata Beef tapeworm rare in US and Canada Cysticerci macroscopically Visible beef measles ingested with raw or undercooked beef T aenia saginata in humans T aenia spp tapeworm N7 7 Scolex attaches in intestine generates a tape of proglottides many years of essentially inapparent infection may follow with shedding of eggs or proglottides in feces T aenia Taef la saginata sagmata gravid SCOlex proglottis T aenia spp eggs T aenia saginata transmission If human feces are applied to land Where cattle ingest them the eggs produce oncospheres which give rise to cysticerci in the bovine tissues T aenia solium Pork tapeworm in U S cases principally imported from Latin America Cysticerci macroscopically visible pork measles ingested with raw or undercooked pork T aenia solium in humans Scolex attaches in intestine generates a tape of proglottides many years of essentially inapparent infection may follow with shedding of eggs or proglottides in feces T aenia solium scolex T aenia solium gravid proglottis T aenia solium transmission If human feces are disposed where swine can ingest them the eggs produce oncospheres which give rise to cysticerci in the swine tissues T aenia solium eggs to humans Taenia solium eggs are infectious perorally for humans ta iers may autoinfect themselves or contaminate food they touch or their feces may transmitthe eggs to other people via food or water the result is cysticercosis often of the CNS in the recipient human Taeniasis Cysticercosis Taeniasis Cysticercosis Taenia solium life cycle fecal undercooked oral w pork T aenia solium neurocysticercosis Diphyllobothrium latum Fish tapeworm Asia Europe the Americas Plerocercoid ingested with fresh water sh Diphyllo bothrium l D latum proglottis D latum de nitive hosts ScoleX attaches in intestine producing the largest tapeworm that infects humans Other species that eat raw sh are also de nitive hosts but produce a low proportion of Viable eggs Eggs shed in feces that reach water infect copepods which are later eaten by sh D latum life cycle D latum in humans Symptoms in humans are usually trivial but vitamin BIZdeficiency anemia sometimes occurs FOODBORNE FLUKES Clonorchis sinensis Opisthorchis spp Metagom39mus yokagawai Heterophyes heterophyes fish ukes Paragonimus westermam39 lung uke Fasciola hepatica liver uke Fasciolopsis buski intestinal uke Clonorchis sinensis Opisthorchis spp Metagonimus yokagawai Heterophyes heterophyes Fish ukes limited geographic distributions Defmitive hosts are humans or other fisheating vertebrates Fish ukes Hermaphroditic adults in liver produce eggs shed in feces Intermediate host is a very speci c snail species Fish are the food vehicle Metacercariae the infectious form Paragonimus westermani Lung uke limited distributions on several continents Eggs from ukes in lung are passed With sputum or swallowed and passed in feces Snail intermediate hosts Food vehicles are crustacea crabs and crayfish eaten raw 2 133 Chin ese Mitten Crab Paraganimus westermani Oriental lung uke life cycle A oumwm egg 7 amp gamma m 4 1x Fascwla hepatlca F asciola hepatica ave Liver uke Widespread but Sporadic in North America Snall 1ntermed1ate host Vehicles for human infection are water plants e g watercress on Which metacercariae have encysted eaten raw Principal de nitive hosts are sheep and cattle other species reported accidental in humans Eggs shed via bile in feces F asciolopsis buski Intestinal uke occurs in southeast Asia 7 largest intestinal uke of humans Main de nitive hosts are humans pigs and dogs Unembryonated eggs shed in feces develop and hatch in fresh water within 3 7 weeks at 27 32OC liver uke life cycle o suunymm m F asciola hepatica the sheep A mmquot Slim 0 ummm 19s A MW 59 um m has Mm ms Fastinbpn39x buslu39 assnau intermediate 1m mm vehicles are Wata39 plants um have ency ed metacercanae maunawums up swarms and fund and waterm mmypms cme Wurld the Me cycles ufmzny quhese parasites Summary can have a sxgm cznt effect m redunng the threat uf sums quhese mm all funds are custumanly tanked Parasites mnsmmed to humans from drinking mm Snurcenvmnde Pavaxneipeme mm m cnmammatmn cum Face Many cmsz WWW Ono1 mammmzm om Face Wm Cryplospom um and amma CryptKw mm mm Tox asma gm Ono1 Parasites transmitted m humans frnm funds cnnmminatad in handlin Snurcenvmnde Parasnespemes Wedmus m cnmzmmznnn mm Harm sth emuwmmwm 0mg me edpwsnn Crypmwarmmhamm 0mg genes Enbmaebamxlaylma 051 tammm 051 as a 639 m mus Parasites transmitted to humans from fruits amp vegetables contaminated in the eld Sourceormode Parasite species Infectiousfoim ofcontam39nat39on Agentinfeces Asca 39suml coides Egg WHENquotde COptosporidlijmpalvun Oocyst so39lg water Cydosporacayetanmsr s Oocyst Entamzebahisto ca C lt 2 FaxMa hepatca Metacercaria FaxIbopsisbuski Metacercaria GI39adia lambfa Cyst TaenlasoI39um Egg proglottis Toxogasma orid39139 Oocyst Parasites transmitted to humans from raw or rare meats Source or mode Parasite species Infectious ofcontam39nation form Infectedfood Taena sagnata Cysticercus animal TaenasoI39um Cysticercus Toxopasmagondi Bradyzoite T39L39 quot 39 quot CvstIIarvaII Parasites transmitted to humans from raw or rare sh amp seafood Source or mode Parasite species Infectious of contamination form Infected sh Anisakids Lana ocean Infected sh Conorchis sinensis etc Metacercan39a freSh Water Diphylobothriumatum Plerocercoid Crustacea Para nimus westermanii Metacercan39a Predictive Modeling I 5 ean 0 Cliver 3 Predictive microbiology oSurvivaI multiplication or death of spoilage organisms or pathogens in foods k oods as ecosystems gages Growth curves oCIassicaI four phases oAssumes monoculture usually fluid suspension a wee exchange of nutrients kibomes WI Standard growth curve Sullonlry Phnle Ruler 3 Dull Bulbs I llu Ruin 4 Bacterial lag Cnum 8 In v o E E E Z 5quot J quota Bxpnrlnm D nu rain Timon Initial growth L MPD st 14 count L I I Type I Growth curve LPD LL GP Mostsought parameters oLag phase duration LPD oExponential growth rate EGR oGeneration time GT 385139 Iog102slope0301sope M um population density MP R la Modeling Process 1 Planning 2 Collection and analysis of data 3 Mathematical descri tion of W ta model developFrJnent 4 Vaxhdation and mamvtenance of model Modified Gompertz equation LogN A De eHU M w ere A B D and M are Mostsought parameters eBM 1 1 LPD M 1 B e EGR Q 8 x GT 03019 BD MPD DA t Generic growth curve ll ll cl Ln rm 1 1 LI I M lliil Time Survival death Q Type 11 Survival curve NaCl vs E coli nnl ml 25 i 0 X 75 100 Log C I LI le lull rs NaCl vs S aureus nnl ml 5 0 75 30 10l o Lag CFUqu llours USDA ARS Pathogen Modeling Program PMP ttg39llwwwarserrcgovlmfslpathogenhtm i Applications of Microbiological Modeling 0 Hygienic efficiency of meat processing operations cooling transport meat Won thawing o h fIife studies for meat po t and dairy products Applications of Microbiological Modeling 0 Validity of regulations check rationale for mandatory codes of practice th gobial fermentation optimum conditions for g t s rter cultures IQ r of desirable microbes Applications of Microbiological Modeling 0 Conditions for enrichment of target microorganisms in cultures bE rocess optimization and XVwon o Pr tformulation o Edu Epn HACCP Pred Microbiol 1 Identify 1 Identify the potential microorganisms hazards and of concern assess their severity at Nifgrent stages on O ng or it Clostridium botulinum Introduction 0 About 90039s gt Certain foods caused typical poisoning gt Emperor Leo VI of Byzantium forbade the quot eof blood sausages Introduction 0 1793 An outbreak caused by blood sausages was described in Wildbad Germany Introduction 1820 Kerner collected m y data on 230 mm cases oftypical 39 poisoning n an V MM 39Magdebwg 0 Disease became known as quotKerner s Diseasequot Mmm Introduction 1897 0 van Ermengem isolated an anaerobic bacterium from cured raw ham that had caused Kerner s Disease in 23 people and killed 3 Nahumth LL Other Findings killed a number of different experimental animals with the same signs as the disease in humans Other Findings on so was D15me proved to b e fairly resistant Introduction van Ermengem called the organism Bacillus botulinus after botnlus Latin for sausage Later named C botulinum Introduction The C butulinum strain isolated by van Ermengem was later designated type B The name of the disease was changed from Kerner s Disease to botulism Back to Germ any 1904 Landm an investigated b otulism caused by canned white beans Landman Findings Cont 1904 The signs and symptoms weretypical l or botulism The antitoxin Landman produced did not crossareact with van Ermengem strain Landman had discovered C botulinum type A How about the US Between 191871922 gt297 cases and 185 deaths gtmainly in California Intro du ction Introduction 1936 C botulinum type E was isolated 1922 C botulznum type C was Isolated gt d l h k d ttl cause para ySIS m c w ens an ca e gtfrom smoked sh that caused botulism in the US and Russia 1929 C botulinum type D was isolated gtfrom cattle that died from paralysis Intro du ction Introduction 1951 Wound botulism was described for the 19601 C nullquotum type F was iSOIated in rst time Denm ark gtfrom liver paste that caused human botulism X Intro du ction Introduction 1985 Hall et al found that a strain of C barati produced type F botulinal toxin 1986 Aureli et al and McCroskey et al isolated strains of C butyricum that gt no reported cases of poisoning with this type produced type E botulinal toxin in man or animals 1973 1996 CDC documented 724 cases of veri ed foodborne botulism in American 1976 Infant botulism was recognized adults mainly associated with homecanned vegetables 1970 C botulinum type G was isolated in Argentina gtfrom soil Illness amp Causative Agent Botulism is a serious paralytic illness It is caused by a nerve toxin that is produced by the bacterium It is a rare illness It is much feared Categories of Human Botulism 1 Foodborne botulism 2 Infant botulism i I W l39 3 Wound botulism 1 nuJ v aquot L 39 1 4 Unclassi ed C Categories of Human Botulism Foodborne botulism gtThis type of food poisoning is caused by the ingestion of foods containing the potent neurotoxin gtThe neurotoxin is formed in the food during growth of C botulinum Categories of Human Botulism Infant botulism gtIt was rst recognized in 1976 gtThis type of poisoning affects infants under the age of 12 months gtIt is caused by the ingestion of C botulian spores Categories of Human Botulism Infant botulism gtThe spores germinate amp multiply colonizing the intestinal tracts of infants and produce neurotoxin gtThe neurotoxin travels through the bloodstream to the central nervous system and causes accid paralysis Categories of Human Botulism Infant botulism gtInfant botulism has been reported in 41 states nationwide gtThe incidence is 1 case per 100000 live births gtCase fatality rate is below 4 Categories of Human Botulism Infant botulism gtIn California the incidence from 1985 to 1995 was 71 cases per 100000 live births gtEstimated medical costcase at 85000 total cost 31 million Categories of Human Botulism Infant botulism gt Honey is now thought to account for no more than 5 o of cases gt California cases may come from spores on wind blown dust Categories of Human Botulism Infant botulism gtHoney is one vehicle that has been associated with infant botulism by a number of laboratory and epidemiological studies Categories of Human Botulism Wound botulism gtThis illness results from the pathogen itself infecting a wound gtFoods are not the vehicle of transmission gtThe microorganism produces the neurotoxin which is transmitted to other parts of the body via the blood gtRare form of illness Categories of Human Botulism Unclassi ed gtResembles infant botulism but affects adults gtC botulinum colonizes the intestinal tract of adults and produces the toxin in vivo gtThought to occur after antibiotic treatment depleted the indigenous intestinal ora Recorded Botulism Cases in the US 1973 1996 Botulism type Rangeyr Total all years Food 8786 724 Infant 0 99 1444 Wound 0 25 103 Unclassified Not avail 39 Classi cation of C botulinum There are seven types of C butulinum gtA B C D E F and G gtbased on the serological speci city of the neurotoxin produced C botulinum Toxins C botulinum produces 39 eight toxins A B C1 C2 D E F and G 39 All are m except CZ Classi cation of C botulinum Types A B E and very rarely F are associated with human botulism foodborne wound and infant types Types C and D affect animals Type G has not been linked to illness up to this date C botulinum Toxins Some strains produce pairs of These are designated subtypes gtThe capital letter identi es the type of toxin in greater amount gtThe lower case letter identi es the type of toxin produced in lesser amount Eagl C botulinum Toxins An example gtstrain isolated from a case of infant botulism was classi ed as subtype Distribution of Serotypes in Human Botulism in the US Type Cases M Deaths quotn A 38 52 B 38 12 E 97 10 F 0 0 Unknown 13 0 C botulinum groups Another classification of C bolulinum strains is based on physiological differences gtgrowth temperature gtpH gtWater activity gtsodium chloride concentration C botulinum Groups C bolulinum strains are divided into four groups gtgroup 1 proteolytic and produce neurotoxins type A B and F gtgroup 11 nonproteolytic and produce neurotoxins type B E and F the most commonly involved in human illness C botulinum Groups C bolulinum strains are divided into four groups gtgroup 111 variably nonproteolytic or proteolytic and produce neurotoxins type C and D gtgroup 1V proteolytic and produce neurotoxin type G Characteristics of C botulinum Gram positive Sporeformer Anaerobic Rods Produce a potent neurotoxm I A DnmettScience Phnln Library Characteristics of C botulinum pH values for growth gtTypes A and proteolytic B Gp 1 pH 495 gtMinimum pH for E Gp 11 is 3 62 at 5 C and 3 54 at 30 C Characteristics of C botulinum Limiting water activity gtType A 095 gtType B 094 gtType E 097 Characteristics of C botulinum Limiting salt concentration for growth gt107712 NaCl gtNonproteolytic most sensitive Characteristics of C botulinum Growth temperature gtType A and proteolytic B Gp I 107500C gtE and nonproteolytic B and F Gp II 337450C gtSpores are highly resistant to freezing Characteristics of C botulinum Redox potential gtOptimum growth occurs at Eh of 7350 mV gtE is the least anaerobic 07100 mV Characteristics of C botulinum Heat resistance de ned gtDecimal reduction time D value 90 kill gtTime required to reduce the microbial population by 1 log cycle Characteristics of C botulinum Heat resistance gt12110C 2500F DRT 0207 021 min for the most resistant A and proteolytic B Characteristics of C botulinum Heat resistance gt12110C 2500F 3 min to achieve lOlzfold reduction standard for low acid canned foods bot cook gt03706 min causes 105fold reduction and is standard for canned cured meats Characteristics of C botulinum I I 0 Radiation resistance MeChanlsm 0f TOXIn To cause 1012 fold reduction gt47 7 54 kGy for type A spores gt10 7 l l kGy for type B spores internalized 6 gt7 7 9 kGy for type E spores gt 12 kGy for type F spores Neurotoxin C binds to neurons 0 prevents release of acetyl choline neurotrasmitter gt48 kGy is the accepted dose for sterilization of food spores Nature of Food Botulism Clinical Symptoms 0 Intoxication 0 Onset is about 18 i 36 hrs after Symptoms molug 39 gtnausea and vomiting ingestion of the food containing the neurotoxin 0 Symptoms vary from a rriild to severe illness Clinical Symptoms Nature of Illness SyrnptonS incIUd Other symptoms include gt neurOIOglcal Slgns u be gtgastrointestinal problems I blurred or double vision cramps I dif culty in speaking or swallowing abdominal pain I fatigue I diarrhea or I lack of muscle coordination and I constipation dif culties in breathing 1 r v Lg Pathogenic Dose Few nanograms of C botulinum neurotoxin can cause illness The neurotoxin produced is probably the most toxic compounds made by a biological system About 1 oz 284 g of this toxin can kill 200 million people Fortunately the incidence of the illness is low Foods Implicated in Botulism Any food that can support the growth of this pathogen or allow the germination of its spores and eventually toxin production can be associated with this illness Low acid foods pHgt46 Foods Implicated in Botulism Homecanned or preserved lowacid vegetables gtasparagus tomatoes beans mushrooms gtpeppers corn baked potato chopped beets gtgarlic in soybean oil Foods Implicated in Botulism North American Indian specialties gtfish and fish eggs gt seal ippers Other implicated foods include luncheon meats ham sausage smoked and salted fish and lobster C botulinum Outbreak In 1994 in Oklahoma a 47year old man was hospitalized for symptoms of progressive dizziness blurred vision slurred speech difficulty swallowing and nausea Twentyfour hours earlier the patient had eaten some home canned green beans and beef and potato stew C botulinum Outbreak Upon testing gtThe green beans tested negative for the toxin gtThe stew tested positive for the toxin C botulinum Outbreak Apparently gtthe stew was cooked gtcovered tightly gtleft out for four days at room temperature an gtthen eaten without reheating Prevention Assurance of destruction or inhibition of C botulinum Keep foods out of the temperature danger zone 44 7 60 C or 40 7 140 F Botulinum toxin is destroyed by heating at 80 C for 30 min or boiling or a few minutes Thus re heating foods properly can be a controlling factor Detection of Organism amp Toxin Compendium of Methods for the Enrichment of culture in cooked liver or cooked meat medium Plating on blood agar or egg yolk agar and incubating anaerobically Microbiological Examination of Foods Detection of Organism amp Toxin Toxin can be detected and typed by mouse inoculation Q Q Assumption Active toxinwill kill mouse An ELISA method has been developed for detection oftoxin a EotuI num Toxin Type A p ww swim ms mmm or magma Form CALCULATION OF FISHER39S EXACT TEST Complaint no Place of outbreak Vehicle StepS Consider only if steps 3 and 4 are not performed on Form Ll ab I cd I ac I bdI Formula for calculation n a b c d Onetailed test pl 1 Observed table I I I vi pll I I I I I Exposure 111 Well Attack Rate vii Cancel any possible factorial I values Atedrank a b ab List individual values from factorials Did not c d c d 11 viii Cancel any possible remaining values eatdunk ix Calculate pl 1 from the remaining values Total acii1 bdiv nv pl2Table I I I I vi pl2 I I I I I Exposure 111 Well Attack Rate vii Cancel any possible factorial I values Atedrank a bil ab List individual values from factorials Did not 071 d cd u viii Cancel any possible remaining values eatdunk ix Calculate pl 2 from the remaining values Total acii1 bdiv nv pl3 Table I I I I vi pl3 I I I I I Exposure 111 Well Attack Rate vii Cancel any possible factorial I values Atedrank 32 biz ab List individual values from factorials Did not C72 CH2 0 d 11 viii Cancel any possible remaining values eatdunk ix Calculate pl 3 from the remaining values Total acii1 bdiv nv Etc continue for all other pvalue needed x plvalue pll pl2 pl3 plx for onetailed test Interpretation If the pvalue is less than or equal to 005 then there is evidence to suggest that the foodbeverage under investigation is related to the observed illness if it is 0005 or less there is strong evidence for this relationship Staphylococcus aureus t Introduction In 1878 Koch observed staphylococci 39 Staphylococcus recognized as a separate genus in 1880 by Pasteur S uureus Properties I In the Greek language gt staphyle a bunch of grapes gt coccus round r 39 quot Introduction 1884 Rosenback grew staphylococci on a solid medium 1884 Sternberg associated staphylococciwi ptomaine formation in cheese that caused human illness Introduction 1894 Denys associated illness with eating of meat from a cow sick with pyogenic staphylococci 1907 Owen recovered staphylococci from dried beef that had caused poisoning characteristic of what now is called staphylococcal food poisoning Introduction 1914 7 Barber related staphylococcal food poisoning to a toxic substance produced in food He isolated staphylococci from contaminated milk that came from a sick cow with mastitis Introduction 0 1929 Dack studied an outbreak of food poisoning caused from eating Xmas cake 0 Rediscovered the role of staphylococci in food poisoning 0 He showed with human volunteers that the isolated staphylococci produced a toxic substance in culture this substance caused typical staphylococcal food poisoning Introduction 194871974 studies demonstrated gtThe presence of preformed enterotoxin in foods that had caused staphylococcal food poisoning gtAntitoxin in the blood of people that had suffered from this type of poisoning S aureus in the US estimated Agent Cases Deaths s aureus 185060 13 2 01 39 Total bacterial 4175565 302 1297 717 Totalfoodborne 13814924 100 1809 100 S aureus 0 In 1994 S aureus was considered to be the cause of one of the most common bacterial food intoxications Holt et al 1994 estimated S aureus food intoxication to be the second most prevalent disease in the US Contemporary Problems Foods associated with staphylococcal food poisoning gtIn the US 7 Meat products eg ham 7 Desserts gtIn Japan 7 Rice balls Seasonal variations Illness amp Causative Agent S aureus causes foodbome intoxication The thermostable enterotoxins and not the bacterium are responsible for the foodborne illness Staphylococcus staphylococcal food poisoning Illness amp Causative Agent S aureus Properties The pathogen produces the toxins 39 only enterOtQXin39PTOdUCing I while growing in the food staphylococc1 cause food p01son1ng When the toxins are ingested by a 39 The ability to PrOduce ent T0t0XinS susceptible person they will cause 15 a550 31at3d Wlth PTOdUCUOn 0f the illness coagulase and heat resistant DNase S aureus Properties S aureus Properties 0 It has a coccus shape 0 S aureus is 0515 pm in diameter 0 Occurs in clusters of irregular arrangement lik Gram positive nonsporeforming the bunch of grapes nonmotile facultative anaerobe 0 May occur singly in pairs or in short chains Coagulase and catalase positive Coagulase Test Coagulase test reactions Suspect colonies are incubated in 2 m1 of Brain Heart Infusion BHI broth for 18 24 hr at 35 37 C 05 m1 coagulase plasma with 05 m1 of EDTA is added to 05 m1 of broth culture and mixed Tubes are incubated and examined after 4 hr C 3 AL GIJL AASE I39E ST S aureus Properties S aureus produces a variety of extracellular enzymes and metabolites The most important metabolite produced is a group of heat stable toxins called enterotoxins staphylococcal enterotoxins POSITIVE S aureus Properties S aureus Properties Temperature range A pH range 40 98 Optimal 6 7 7 478 C Opt 35 37 C Salt tolerant 10 20 NaCl Enterotoxins produced between 10 46 C Opt 40 45 C S aureus Properties Environmental Effects Can grow at a sucrose concentration 210 NaCI inhibits SEA and SEE up to 50 60 production Water activity as low as 086 under EnterOtOXinS are not formed aerobic conditions and 090 under Below pH 53 at 30 C anaerobic conditions Below pH 56 at 100C Greater toxin production under aerobic conditions Minimal water activity 086 for growth Water Activity Enterotoxin production occurs at 086 7 099 Opt 099 Reducing a minimizes production of enterotoxins 7090 aW reduces SEB by 9099 Manama 1998 Microbial Ecology S aureus does not compete well with the normal ora of most foods S uureus Toxins S aureus is the common species associated with food intoxication 12 enterotoxins A B C D E G H 1 J K L M Three variants of SEC 7 C1 C2 C3 minor antigenic differences S uureus Toxins Staphylococcal enterotoxin A SEA most common in gastroenteritis S uureus Toxins Enterotoxins are simple proteins asin soluble in water and salt solutions Resistant to trypsin chymotrypsin and papain Pepsin destroys the toxin at pH 2 Toxin is resistant to radiation 200 kGy and boiling resists 12110C for 05 hr S uureus Enterotoxins Low molecular weight N30 kDa simple proteins Heat resistant simple S aureus itself is not heat resistant Enterotoxins A and D are the most heat resistan When active A and D exhibit proteolytic enzyme resistance Pathogenesis target area Enterotoxins expected to act on the receptors in the gut that transmit impulse to medullary centers Clinical Sympto 0 S uureus enterotoxins cause gt severe gastroenteritis gt nausea vomiting retching abdominal cramps sweating chills prostration weak pulse shock shallow respiration subnormal body temperatures S aureus Food Poisoning About 2106 cellsgram of S aureus in food is needed for toxin production 0 About 200 ng of toxin can cause illness in hum ans j S aureus Food Poisoning Onset of illness takes 60 min 8 hr following ingestion of the toxin containing food 0 Most illness however occurs within 2 4 hr 0 Recovery is within 24 48 hr Illness is rarely fatal Clinical Symptoms The enterotoxins acts on the receptors in the gut that transmit impulse to medullar39y centers 0 Treatment of patients consists of bed rest and maintenance of body uids and electrolytes S aureus Infections S aureus is a feared hospital pathogen Sometimes it can be very virulent and often resistant to antibiotics I I How Is S aureux Introduced to Food s m is commonly found in gt Fingertips Hair and skin Found in more than 50 or healthy people Found on skins or hides or animals Found in the environment How Is S aureux Introduced to Food I Any food that requires handling and preparation is susceptible for contamination I S aureux is also found on the skin or hides of animals I Crossacontaminatl39on may result from these animals during slaughtering Foods Often Incriminated I Meats and meatproducts I Poultry and Fish I Creamalilled baked goods I Baked foods I Potato Salad I Salads containing any of the above items ny nutrientarich moist food that is temperature abuse Food Sources for Staphylococcal Outbreaks 19731987 Ballet 1 ma Contributing Factors I Improper storage and holding temperatures I Inadequate cookingprocessing temperatures I Contaminated Equipment I Unsal e food sources I Poor personal hygiene gt 10 r 50 adults are reservoirs oI39S mm Prevention I Adequate storage and refrigeration of foods I Not preparing l oods far in advance I Adequate cooking andor heat processing I Avoiding poor personal hygiene I Not holding l oods between 40 7 140 F 447 60 C for prolonged periods I 407135 F 44757 C new numbers Pathogen Detection Laboratory media gtTrypticase soy broth with 10 NaCl gtMannitol salt agar gtBairdParker agar Indicators for the Presence of S aureus 0 Coagulase Test 0 Thermostable Nuclease Test TNase Polymerase Chain Reaction PCR TN ase Testing 0 Culture is boiled for 15 min Toluidine blue agar plates are prepared 0 2 mm wells are dug in the plates and filled with the boiled cultures 0 Plates incubated for 2 4 hr at 37 50 C 0 Pink halos around wells indicates positive reaction Maradona 199s Polymerase Chain Reaction PCR 0 Thermostable DNA polymerase catalyzes the gene probe amplification 0 Amplified DNA is detected by hybridization ring using radio and nonradiolabeled probes 0 Can amplify a single DNA molecule to 107 molecu es Maradona 1993 Detection Methods of Enterotoxins Biological Immunological many including kits Biological Detection 0 Each new toxin type had to be detected biologically 0 Biological subjects used are cats kittens and monkeys Kittensemetic response 0 Can determine the enterotoxin activity by observing responses 0 Monkeys used to simulate human response Maradona 1998 Immunological Detection Microslide Agglutination RadioimmunoassayRIA Enzyme Linked Immunosorbent assay ELISA Enzyme Linked Fluorescent Inmmunoassay ELFA Microslide Test Linear migration of antibody and antigen in a AOAC recommended method Sensitivity level of 50 ngml Easy to read results Disadvantages r lVIust concentrate sample from 100 g to 02 ml 7 Time consuming 1 days Mmdnnz 1998 Gel Diffusion Agar is prepared with antiserum and aspirated into Pasteur pipette Pasteur pipette is sealed Liquid sample is added on top of solidi ed Pipettes are incubated at 37quotC for 24 hr Precipitant band is formed il toxin is present rung was Gel Diffusion Bands of S aureus Enterotoxins Suurce Dr DYC Fung UCDms VM PHRQSEI HACCP Pr 0 The emphasis is being direc detecting food safety hazards upstream in the production or manufacturing process rather than in the finished product 0 HACCP is not a standalone system o It is complemented by other programs such as GMPs SOPs and SSOPs nd Posth arvest mm Tajkanmx DVM my UCDms VM PHRQSEI o Mandated by FDA as a contro system for seafood 0 Recently for juices 0 Growing interest in using HACCP to control the safety of live animal production as well as produce production ie preharvest food safety H history mm Tajkanmx DVM my UCDms VM PHRQSEI HACCP Pr nd Postharvest 0 Traditionally the safety of fo has been controlled and still is inspection of the final product 0 Hazard Analysis and Critical Control HACCP system the process of food inspection is being modernized Mzhrdad Tajkanm DVM my UCDms VM PHRQSEI used by the food industry 0 In 1996 HACCP Was mandated by US DAFSIS in meat and poultry slaughter andor processing facilities in an attempt to enforce more strict food safety measures Mzhrdad Tajkanm DVM my UCDms VM PHRQSEI o The 1809000 system is set to pr common standards of quality duri production or manufacturing of produ s nationally or internationally agree on quality of the product 0 HACCP Safety Mzhrdad Tajkanm DVM my UCDms VM PHRQSEI supplier veri cation and validation o This requires a company policy de nition and quality manual With de nition of responsibilities for management and employees prerequisite programs and HACCP plan imp ementation Mehnlm Tnhanmi DVM PhD UCDms VM PHR25EI 0 Preparing SSOP programs and measures for implementing the food safety program Preparing the HACCP team and effective combination of selfassessment With application of internal auditing management review application of all legal requirements and supplier evaluation are other concerns in this system recording systems a Mehnlarl Tnhanm DVM PhD UCDms VM PHR25EI applicable quality management syste s an prerequisite programs o It extends the approach of the ISO 9001 2000 quality management systems standard which does not specifically address food safety Mehnlm Tnhanmi DVM PhD UCDms VM PHR25EI o Principle 0 Principle control points CCPs o Principle for preventive measures associated with each C o Principle 4 Establish procedures to 39 C monitor 0 Principle 5 Establish corrective actions 0 Principle 6 Establish record keeping system 0 Principle 7 Establish verification procedures M h39d ml mm39m CCP PrInCIples 1 Hazar 2 Identify the cr 39c s m E39 3 Establish critical limi M PhD UCDms VM PHR25EI o i Hazards ofsigni cance are identi ed 0 ii Likely hazards are selected 0 iii Identi ed hazards can be used for developing preventive measures 0 Hazards can be biological chemical or physical in nature and the potential risk of each hazard is assessed based on is likelihood of occurrence and its zmgtymmmm u UCDms VM PHR25 Principle 2 Identify the critic points can be prev acceptable levels an be cooking chilling sanitation cross contamination or employee and environmental hygiene A cop is a point step or procedure at which control can be applied and a food safety hazar A cop Deczszml Tree is helpful in assigning CCPs Principles ented eliminated or reduced to Mehnlarl Tnhanm DVM PhD UCDms VM PHR25EI 5mm wmm m m mm m mmuwji lawhuhs sum nm ccP Mzhrdzd 751mm DVM my UCDms Viman Principles 0 Principle 3 Establish critical limits for preventive measures associated with each CCP 0 Critical limits are the boundaries for safety for each CCP and may be limiw With respect to temperature time meat patty thickness Water activity pH available chlorine etc 0 Critical limits may be derived from regulatory standards or guidelines literature experiments and expert o inion Mzhrdad Tajkanm DVM my UCDms Viman Principle 4Establish procedur monitor CCPs 0 Monitoring is a planned sequence of observations and measurements to assess Whether a CCP is under control and to produce an accurate record 0 This record can be used in case of complains about the product and is also used in the Veri cation of Mzhrdzd 751mm DVM my UCDms Viman Principle 4Establish procedu monitor CCPs o The measurements for monitoring are Visual observations temperature time pH Water activity etc o The measurements must be done online there is no time to Wait for lengthy laboratory tests 0 There must be Written documentation for Who has the responsibility for monitoring Mzhrdad Tajkanm DVM my UCDms Viman Principles Principle 5 Establish corrective actions o Corrective actions are taken to get the process under control when monitoring shows a deviation has occurred and a critical limit has been exceeded 0 There must be Written instructions for actions to be taken reprocess condemn etc when critical limits have been exceeded Mzhrdzd 751mm DVM my UCDms Viman o Principle 6 Establish record system 0 This system is established to document the HACCP system 0 This is necessary for internal audits and for Veri cation of the HACCP system sometimes y 39r parties 0 It is also important in case of consumer complaint Mzhrdad Tajkanm DVM my UCDms Viman Principles Principle 7 Establish veri 39 procedures 0 Veri cation procedures indicate Wh the HACCP system in place is Working properly or not 0 Veri cation is based on the HACCP entation and may include internal audits andor veri cation done by a third party eg ouwide consultant 0 Veri cation may include validation studies ie laboratory testing of samples of food andor the environment Mzhrdzd Tajkanmi DVM my UCDms Viman o GMPs are practices and procedur are conducted by food processors to insure the safety of food for human consumption 0 GMPs take into account personnel equipment process or operation and the environment of food production 0 GMPs fall under thejurisdiction ofthe Food and Drug Administration FDACFR 21 Part1 10 and CFR 21 Mzhrdad Tajkanm DVM my UCDms Viman Good Manufactu g Practices 1 Personnel Disease Control Cleanliness Education and Training Supervision Mzhrdzd Tajkanmi DVM my UCDms Viman Good Manu 2 Equipment 0 Plant equipment and utensils need to adequately cleanable and corrosionresi materials uring Practices 0 The design of the equipment should not allo adultemtion of food With metal fragmenw lubricanw fuel contaminated Water etc o Nonfoodcontact equipment as Well as holding conveying and manufacturing systems should have designs that enable maintenance of proper sanitary conditions Mzhrdad Tajkanm DVM my UCDms Viman Good Manu uring Practices 3 Processing Operations All food processing operations including receiving segregating preparing manu acturing packing inspecting storing and transporting should be conducted under adequate and controlled sanitary conditions to ensure that food is t for human consumption Mzhrdzd Tajkanmi DVM my UCDms Viman Good Ma cturing Practices 4 Environment plant and gro 0 Food plans and the grounds about them should be adequately maintaine and kept under conditions that Will minimize and protect the contamination of food 0 light bulbs xtures and skylights should be adequately installed to prevent food contamination if glass breaks Additionally proper lighting and ventilation should be provided in wor areas Mzhrdad Tajkanm DVM my UCDms Viman 0 Similar to GMPs standard operatr procedures SOPs fall under FDA s o SOPs are plantspeci c 0 An SOP should de ne who is doing thejob why this job is done what it is the steps involved in completing the job any critical time limiw for the task and what are the corrective actions that must be taken if the job was performed incorrectly mm mm DVM my UCDms Viman o Sanitation standard operati procedures SSOPs are plant specific operations 0 SSOPs are regulated by the United States Department of Agriculture USDA 0 Cleaning and maintenance of sanitary conditions are vital for providing consumers with wholesome and safe food Mzhrdad Tajkanm DVM my UCDms Viman 0 Cleaning and sanitizing comp should be stored away from food39 i separate areas 0 To maintain a sanitary water supply an adequate plumbing system must be in o This should allow suf cient quantities of water to be moved into and throughout the plant as needed with proper drainage release or discharge of excess or waste ter 0 A proper sewage disposal system must be mmnmmmvmpm In P ace UchiszImsn Thank yo Mzhrdad Tajkanm DVM my UCDms Viman 250D7 1 PHR 250 April 2007 Listeria monocytogenes Adapted from Dr Linda Harris PHR 150 notes 2006 L monocytogenes was first described in 1923 Prior to 1982 L monocytogenes was recognized as a cause of abortions and encephalitis in many animals particularly cattle and sheep and was thought to be associated with contaminated animal feed or silage While it was recognized as a cause of human illness in 1929 it was not until 1981 that a foodbome association was widely accepted The organism its epidemiology mechanisms of virulence occurrence and methods of detection in foods have been extensively reviewed Bell and Kyriakides 1998 Johnson et al 1990 Farber and Peterkin 1991 Farber 1993 Pearson and Marth 1990 Ryser and Marth 1999 General characteristics L monocytogenes is a grampositive ovoid to rodshaped bacteria that is ubiquitous in the environment It is a facultative anaerobe and acid but not gas is produced from glucose The organism is capable of multiplying at temperatures between approximately 0 and 45 C it is a psychrotroph it is relatively resistant to NaCl growth at 10 survival at 20 to 30 and low pH is not inhibited by carbon dioxide and can survive many processing techniques such as freezing and drying Farber and Peterkin 1991 Lammerding and Doyle 1990 Table 1 indicates limits for growth of L monocytogenes under ideal laboratory conditions Limits for growth may be more restrictive in the conditions found in food systems Table 1 Growth characteristics of L monocytogenes under otherwise optimum conditions Adapted from ICMSF 1996 Minimum Optimum Maximum Temperature C 04 37 45 pH 439 70 94 NaCl growth at 10 Water activity 092 The Canadian regulatory policy on L monocytogenes includes the following growth parameters for readytoeat products Read to eat RTE foods not su ortin the rowth of L mom to enes include the followin Farber and Harwi 1996 1 pH 50 55 and water activity lt095 2 pH lt 50 regardless of water activity 3 water activity of less than or equal to 092 regardless of pH 4 frozen foods 250D7 2 Table 2 Approximate lag and generation times for L monocytogenes generated using the USDA Pathogen Modeling Program Version 60 for a pH of 60 and water activity of 098 Temperature C Lag time days Generation time hours 4 1249 196 6 891 132 8 646 91 10 476 64 12 356 46 14 271 34 16 209 25 Taxonomy The genus Listeria is comprised of siX species L monocytogenes L innocua L welshimeri L seeligerz39 L grayi and L ivanovii On rare occassions L seeligerz39 and L ivanovz39z39 have been implicated in human infections However L monocytogenes is the only species considered to be of public health signi cance Serolog All 13 serotypes of L monocytogenes may cause human listeriosis however 95 of human isolates are 12a l2b or 4b Serotype 4b strains are responsible for 33 to 50 of human listeriosis worldwide This serotype has also been responsible for most recorded foodborne outbreaks Reservoirs L monocytogenes is widely distributed in the environment It can be found in decaying vegetation in soils animal and human feces sewage silage and water L monocytogenes has been isolated from a wide range of retail foods Farber et al 1989 Farber and Peterkin 1991 Although numbers are often very low in these products multiplication of L monocytogenes can potentially occur during refrigerated retail and home storage The psychrotrophic nature of L monocytogenes makes it of particular concern in refrigerated foods with extended shelf life Outbreaks of listeriosis have been associated with vegetable dairy and meat products It is estimated that 80 to 90 of listeriosis cases are linked to ingestion of contaminated food however demonstration of foodbome listeriosis is relatively rare and most cases are sporadic Listeriosis Infective dose The infectious dose is unknown but thought to be highly strain and host dependent It is likely that lt1000 CFU is of no concern to healthy adults However it is assumed that this level will cause illness in susceptible persons Incubation period 250D7 3 24 hours to 91 days Smptoms Symptoms range from ulike to septicemia and meningitis Table 3 Listeriosis refers to the more serious lifethreatening illnesses while gastroenteritis is the relatively mild illness experienced by healthy adults Pregnant women newborns elderly and immunocompromised individuals are most susceptible and experience a more severe illness Case fatality rates for these groups range from 13 to 34 Farber and Peterkin 1991 Virulence Factors L monocytogenes is an intracellular parasite Abnormalities in Tcell immunity increase the risk of listeriosis The Tcell response in the first few days following infection is important to the subsequent outcome of the disease Considerable progress has been made in the past decade in understanding the pathogenesis of L monocytogenes Eight genes clustered on the chromosome are associated with virulence L monocytogenes cells cross the intestinal barrier via intestinal epithelial cells or the M cells of Peyer s patches The organism is internalized by phagosomes Surface proteins intemalin and p60 are thought to aid internalization of L monocytogenes Once internalized within a phagosome the vacuole membrane is lysed and L monocytogenes is released to the cytoplasm where it can multiply Listeriolysin O and a phosphatidylinositol phospholipase C are involved in the lytic process An essential component of virulence is the ability of L monocytogenes to spread directly from cell to cell To do this the organism uses the host cell actin machinery continuously assembling an actin tail at a pole of the bacterial cell surface This serves to propel the bacterium across the cytoplasm pushing the organism against the host cell membrane thus forming a protrusion which can be ingested by an adjacent cell Three genes mpl actl and pch have been linked to this process The resulting vacuole is lysed releasing L monocytogenes into the cytoplasm of the newly infected cell The phagosomes are transported via the blood to the lymph nodes liver and spleen Further dissemination of the organism via the bloodstream to the brain or placenta in the pregnant woman occurs giving rise to the various forms of the illness 250D7 4 Table 3 Illness caused by L mtmocptogenes Adapted from Bell and Ky akides 1998 Type of Listeriosis Zoonotic infection Infection during pregnancy listeriosis Neonatal infection listeriosis Infection of non pregnant adults and children gt1 month listeriosis Gastroenteritis Nature of Infection S everity Time to Onset Local infection of skin lesions Acquired following the consumption of contaminated food Infection of newbom babies from infected mother during birth or due to crossinfection from one neonate in the hospital to other babies Acquired following the consumption of contaminated food Consumption of food with exceptionally high levels of L monocytogenes gt10 per ml Mild and selfresolving Mild u like illness or asymptomatic in the mother but serious implications for unborn infant including spontaneous abortion fetal death stillbirth and meningitis Infection more common in third trimester Can be extremely severe resulting in meningitis and death Asymptomatic or mild illness which may progress to central nervous system infections such as meningitis Most common in immunocompromised or elderly Vomiting and diarrhea sometimes progressing to bacteremia but usually selfresolving 12 days Varies from 1 day to several months 12 days usually from congenital infection prior to birth Illness may occur within 1 day or up to several months lt24 h after consumption Most cases of listeriosis are sporadic and not outbreak associated Recent Foodnet data indicate that 2004 diagnosed infections range from 027 cases per 1000000 population httpwwwcdcgovmmwrm 39 39 39 1 AaZhtm 250D7 5 Outbreaks of Listeriosis Table 4 Everml of foodborne outbreaks of listeriosis Year Country Cases Food Outbreak Food deaths serotype Isolate 198081 Canada 41 18 Coleslaw 4b Yes 1983 USA 49 14 Pasteurized milk 4b 198387 Switzerland 122 34 Vacherin cheese 4b Yes 1985 USA 142 48 Mexicanstyle soft cheese 4b Yes 198789 UK gt350 gt90 Belgian pate 4b Yes 1992 New Zealand 4 2 Smoked mussels 12a Yes 1992 France 279 63 Pork tongue in aspic 4b Yes 1994 USA 45 0 Chocolate milk 12b Yes 1995 France 20 4 Rawmilk soft cheese 4b 199899 22 states US gt100 20 Hotdogsdeli meats 4b Yes 1999 NY CN MD 11 3 Pate implicated No 2000 10 states US 29 7 Deli turkey meat 4b Yes Representative outbreaks Coleslaw 1981 Maritime Provinces of Canada Product type Chopped cabbage and carrot sold premixed at retail Levels not known Serotype 4b Extent 41 cases 18 deaths 2 adults and 16 fetal or newborn Comments Cabbage was suspected to be contaminated with L monocytogenes from uncomposted sheep manure Sheep were suspected to have had Listeria meningitis Cabbage was stored for extended periods of time prior to shredding No antilisterial processes were applied Control Options Apply good agricultural practices Control use of manure Storage at temperatures to prevent the growth of L monocytogenes lt1 C or storage for short period of time lt10 days Mexican style white cheese 1985 Los Angeles County CA Linnan et al 1988 Product type Soft cheese pH 66 Levels not known Serotype 4b Extent 145 cases 64 deaths Comments Environment and equipment were grossly contaminated with L monocytogenes even after clean up Raw milk deliveries allegedly exceeded pasteurization capacity of plant Control Options Adequate pasteurization Proper sanitation Chocolate milk 1995 Illinois Product type Pasteurized chocolate milk Levels in Implicated Food 107 109 CFUml Extent 45 persons gastroenteritis 250D7 6 Comments Outbreak strain was isolated from stool samples of infected individuals from a tank drain at the manufacturing plant and from unopened packs of the implicated milk Milk was pasteurized and passed to a holding tank prior to lling The jacket of holding tank was in poor state of repair and refrigerant could not be used Lining of the holding tank jacket was not intact Milk leaked into the jacket where it stayed until the tank emptied Product could reenter the vessel and contaminate the remaining product being filled Sanitizer sprayballs were blocked and it was likely that insufficient cleaning took place Cartons were taken to the picnic 2 hours unrefrigerated then refrigerated then unrefrigerated for several hours Control Options Properly functioning equipment Good sanitation program Temperature control Hot Dogs and Deli Meats August 1998 January 99 Multi state CDC 1998 1999 Product type Hot dogs and deli meats Levels unknown Extent Over 100 people 15 deaths 6 miscarriages Comments Construction dust at the plant is believed to have contaminated the product in the packaging room Control Options Proper sanitation during packaging of product Postpackaging pasteurization Sporadic Cases 198687 CDC Case Control Study Hotdogs not reheated undercooked chicken 1988 7 1990 CDC Case Control Study Soft cheese food from delicatessin counters undercooked poultry Risk Assessment FDAUSDAa 20031 Ranks 1 to 6 High Risk per serving Deli meats frankfurters not reheated patemeat spreads unpasteurized uid milk smoked seafood cooked ready to eat crustaceans Ranks 1 Very High Risk per annum Deli meats Ranks 1 to 3 High Risk per annum Pasteurized uid milk high fat and other dairy products frankfurters not reheated Impact of Foodborne Illness With improvements in medical technology the proportion of the population susceptible to food borne listeriosis continues to rise The numbers and types of foods in which L monocytogenes is able to survive and grow readytoeat modified atmosphere packaged and chilled foods also continue to increase The economic impact of L monocytogenes is enormous in terms of human health medical costs loss of life and loss of revenue to the food industry recalls zero tolerance Estimated foodbome cases in the US annually 1526 7 1767 Estimated deaths 378 485 Annual estimated medical costs and productivity losses are 02 to 03 billion dollars Buzby et al 1996 250D7 7 Zero tolerance FSIS and FDA don t necessarily set tolerances for pathogens Pathogens are considered an adulterant in RTE foods Zero is de ned by sample size and sensitivity of the diagnostic test In 1985 the FDA began monitoring dairy products for L monocytogenes after a particularly large outbreak of listeriosis associated with cheese In 1989 the CDC published a report of a case of listeriosis from the consumption of turkey franks In response the USDA initiated a microbiological surveillance program for L monocytogenes in readytoeat meats and initiated a zero tolerance policy prohibiting the sale of readytoeat meat products contaminated with L monocytogenes Shortly thereafter this policy was expanded to include all readytoeat foods in practice this is interpreted as processed readytoeat foods RTE foods are those products that have been processed so that they may be safely consumed without further preparation by the consumer This policy designated L monocytogenes an quotadulteran quot Any readytoeat food that contains this organism in a 50 g sample can be considered adulterated and subject to a Class I recall andor seizure Class I recalls are classi ed as a situation in which there is a reasonable probability that the use of or exposure to a product will cause serious adverse health consequences In the US from October 1 1991 to September 30 1992 16 of all recalled products and 57 of class I recalls could be attributed to L monocytogenes Venugopal et al 1996 It has been suggested that these procedures as well as consumer educational efforts lead to a reduction in illness and death associated with this organism Tappero et al 1995 When 1989 and 1993 data were compared a reduction in illness and death of 44 and 48 respectively was observed Similar trends were noted in the UK Other countries including Canada have adopted more moderate approaches based on risk see Farber and Harwig 1996 250D7 8 Table 5 Canadian Compliance Criteria for Listeria monocytogenes in ready to eat RTE foods Category Action Level for GMP Immediate Action Followup LM Status Action 1 RTE foods causally gt0 CFU50 g NA Class Irecall to retail linked to listeriosis level This list presently includes soft cheese Consideration of liver pate coleslaw mix Public Alert with shelf life gt10 days jellied pork Appropriate followup ton at plant level 2 All other RTE foods gt0 CFU25 g NA Class II recall to retail supporting growth of level LM with refrigerated shelflife gt10 days Health alert consideration Appropriate followup at plant level 3 RTE foods D1CFU g Adequate Allow sale Appropriate supporting growth of GMP followup at LM with refrigerated plant level shelflife D 10 days and all RTE foods not supporting growth D1CFU g Inadequate Consideration of Class Appropriate or no GMP II recall or stop sale followup at plant level D1CFU g NA Class II recall or stop Appropriate sale followup at plant level Control in the Food Processing Environment Dry processing areas 959 Cleaning and sanitizing Human hygiene Environmental and product sampling Separation of raw product and processing areas Processing controls monitored records maintained 250D7 9 Further Reading Bell C and A Kyriakides 1998 Listeria A practical approach to the organism and its control in foods Blackie Academic amp Professional London Buzby JC T Roberts CT J Lin J M MacDonald 1996 Bacterial foodbome disease Medical costs and productivity losses USDA Agricultural Economic Report No 741 CDC 1998 Multistate outbreak of listeriosis 7 United States 1998 MMWR 4710851086 CDC 1999 Update Multistate outbreak oflisteriosis 7 United States 1998 7 1999 MMWR 471117 1118 Farber JM 1993 Current research on Listeria monocytogenes in foods an overview J Food Prot 56640643 Farber JM and J Harwig 1996 The Canadian position of Listeria monocytogenes in ready toeat foods Food Control 7253258 Farber JM and PI Peterkin 1991 Listeria monocytogenes a foodbome pathogen Microbiol Rev 55476511 Johnson JL MP Doyle and RG Cassens 1990 Listeria monocytogenes and other Listeria spp in meat and meat products a review J Food Prot 538191 Lammerding AM and MP Doyle 1990 Stability of Listeria monocytogenes to nonthermal processing conditions In AJ Miller JL Smith and GA Somkuti ed Foodbome Listeriosis P 195202 Soc Ind Microbiol Linnan MJ L Mascola XD Lou VGoulet S May C Salminen DW Hird ML Yonkura PHayes R Weaver A Audurier BD Plikaytis SL Fannin A Kleks and CV Broome 1988 Epidemic listeriosis associated with Mexicanstyle cheese N Engl J Med 319824 828 Pagotto F N Comeau and F Farber 2006 Listeria monocytogenes infections pp 3137340 In Riemann H P and D O Cliver eds Foodbome Infections and Intoxications 3d ed Academic Press Elsevier London Amsterdam Pearson LJ and EH Marth 1990 Listeria monocytogenes threat to a safe food supply A review J Dairy Sci 73912928 Pinner R W et al 1992 The role of foods in sporadic listeriosis II Microbiolgic and epidemiologic investigation J Amer Med Assoc 26720462050 Schleck WF 111 PM Lavigne RA Bortolussi AC Allen EV Haldane AJ Wort A W Hightower SE Johnson SH King ES Nicholls and CV Broome 1983 Epidemic listeriosis evidence for transmission by food N Engl J Med 308203206 Shank FR EL Elliot 1 K Wachsmuth and ME Losikoff 1996 US position on Listeria monocytogenes in foods Food Control 7229234 Smith JL 1999 Foodbome infections during pregnancy J Food Prot 62818829 Tappero JW A Schuchat KA Deaver L Mascola JD Wenger 1995 Reduction in the incidence of human listeriosis in the United States Effectiveness of prevention efforts JAMA 27311181122 Tompkin R B VN Scott DT Bernard WH Sveum and KSullivan Gombas 1999 Guidelines to prevent postprocessing contamination from Listeria monocytogenes Dairy Food Enviom San 19551562 Venugopal R L Tollefson FN Hyman B Timbo R E Joyce and KC Klontz 1996 Recalls of foods and cosmetics by the US Food and Drug Administration J Food Prot 59876880 PHR 2 50 42507 6p Bacillus cereus Mehrdad Tajkarimi Materials from Maha Hajmeer Introduction Bacillus cereus is a Grampositive sporeforming microorganism capable of causing foodbome disease At present three enterotoxins able to cause the diarrheal syndrome have been described hemolysin BL HBL nonhemolytic enterotoxin NHE and cytotoxin K HBL and NHE are threecomponent proteins whereas cytotoxin K is a single protein toxin Symptoms caused by the latter toxin are more severe and may even involve necrosis In general the onset of symptoms is within 6 to 24 h after consumption of the incriminated food B cereus food poisoning is underestimated probably because of the short duration of the illness 24 h History In 1887 Bacillus cereus isolated from air in a cowshed by Frankland and Frankland Since 1950 many outbreaks from a variety of foods including meat and vegetable soups cooked meat and poultry sh milk and ice cream were described in Europe In 1969 the rst wellcharacterized B cereus outbreak in the USA was documented Since 1971 a number of B cereus poisonings of a different type called the vomiting type were reported This type of poisoning was characterized by an acute attack of nausea and vomiting 15 h after consumption of the incriminated meal Sometimes the incubation time was as short as 15730 min or as long as 6712 h Almost all the vomiting type outbreaks were associated with consumption of cooked rice This type ofr 39 39 food r B Cereus in the US Table 1 Best estimates of the annual cases and deaths caused by B cereus in the US Agent Cases Percent Deaths Percent B cereus 27360 02 0 0 Total bacterial 4175565 302 1297 717 Total foodborne 13814924 100 1809 100 Recent estimates indicate there are 84000 cases of B cereus illness annually in the US with an estimate cost of 430 case a total of 36 million CDC 199872002 37 outbreaks 571 cases no deaths 250H6 2 Classi cation of B cereus The genus Bacillus is very diverse it is presently divided into siX subgroups based on spore morphology B cereus falls in the Bacillus subtilis group and it is closely related toB anthracis B mycoz39des and B thuringiensis Some argue because of the close relatedness that the three later species should be classi ed as subspecies ofB cereus B cereus and B anthracis are both recognized as pathogens but the former is implicated with foodbome disease B anthracis can infect perorally but is inefficient Table 2 Criteria to differentiate among four closely related Bacillus spp Species Colony Motile Hemolysis Susceptibility Parasporal Virulent to Penicillin Body to Mice B cereus White Yes Yes No No No B anthracis White No No Yes No Yes B mycoides Rhizoid No No No No No B thuringiensis White Yes Yes No Yes No Grey Factors Affecting Growth of B cereus Growth temperature range from 7749 C 44 671202 F with a minimum of 45 C 392741 F and a maximum around 48750 C 1184122 F Generally spore germination temperature range from 8730 C 464P86 F pH range for growth pH 49793 Minimum water activity 0914193 Salt concentration as high as 75 NaCl some tolerate 10 Eh no effect Thermal D value for spores at 100 C around 3 min but some spores much more resistant Spores are more resistant to irradiation than vegetative cells The dose for 90 reduction of spores is 125 4kGy and 017065 kGy of vegetative cells 250H6 3 Name of Illness Caused by B cereus B cereus food poisoning is the general name used for the illness However B cereus has two recognized types of foodbome illness diarrheal and emetic The emetic syndrome is caused by cereulide a heat and pHstable peptide toxin Consumption of food contaminated with this toxin may lead to emesis between 30 min and 5 h after ingestion The diarrhoeal syndrome is caused by enterotoxins that are produced during growth of B cereus in the small intestine Two different metabolites or toxins cause these two types Other nonfood borne illnesses can be caused by this pathogen including respiratory tract and wound infections The diarrheal illness more common in North America and Europe is caused by a high molecular weight protein while the emetic or vomiting type more common in Japan than the diarrheal type of food poisoning is caused by a low molecular weight and heatstable protein In some outbreaks there seems to be an overlap between the diarrheal and the emetic types of illness Nature of Illness Generally symptoms are transient and mild possibly a contributor to underreporting Large numbers of cells are needed to cause illness Food could be spoiled by the time the microbial load reached the level required to cause illness The symptoms of B cereus diarrheal type food poisoning include abdominal pain watery diarrhea rectal tenesmus moderate nausea that may accompany diarrhea seldom vomiting and no fever Symptoms develop within 615 hrs and can persist for 24 hrs This syndrome is rather mild and tends to mimic the symptoms of C lostridz39um perfrz39ngens food poisoning The signs of B cereus emetic type food poisoning include nausea and vomiting Also abdominal cramps andor diarrhea may occur The incubation period is about 175 h The symptoms of this illness mimic those of Staphylococcus aureus food poisoning Other observed complications of B cereus infection include gangrene septic meningitis cellulitis lung abscesses infant death endocarditis and severe systemic and pyogenic infections A comparison of diarrheal and emetic types of B cereus food poisoning is included in Table 3 Also a comparison of food poisoning caused by B cereus C perfringens and S aureus is provided in Table 4 250H6 4 Table 3 Comparison of diarrheal and emetic types of B cereus food poisoning Syndrome Incubation Duration Dose Foods Diarrheal 8716 h 12724 h 1037107 CFU Milk soup meat ingested products puddings Emetic 175 h 12724 h 105708 per g of food Rice pasta noodles pastries 1 Granum PE 1994 Bacillus cereus and its toxins J Appl Bacterial Symp Suppl 76 618668 Table 4 Comparison of food poisoning caused by different bacterial agentsl Pathogen Incubation Duration Dominating Type of Frequently 11 of Illness Signs Disease Implicated Food h B cereus 8716 12724 Diarrhea Toxico Meat products diarrhea infection soups vegetables puddings and sauces C per ingens 8716 12724 Diarrhea Toxico Meats meat infection products and gravy B cereus 175 12724 Diarrhea Intoxication Fried rice from emetic fairly Chinese restaurants common and take outquot vomiting shops S aureus 175 12724 Diarrhea Intoxication Cooked meats and Vomiting poultry and dairy products T Source Gilbert R and Kramer JM 1987 In Progress in Food Safety Cliver DO and Cochrane BA eds pp 8593 Food Research Institute University of Wisconsin Madison Outbreaks reported since 1950 in several countries including Norway Denmark Italy the Netherlands Hungary Sweden Poland Rumania the USSR the United States Germany and Canada Outbreaks reported since 1971 in Great Britain Canada Australia the Netherlands Finland the United 96 96 States and Japan 250H6 5 Reservoirs B cereus is ubiquitous in nature It is believed that the primary habitat of B cereus is soil It is found rather frequently in foods such as meats poultry milk cereals starches herbs and spices Products Associated with B cereus Food Poisoning Foods implicated with the diarrheal type of B cereus poisoning include milk vegetables meat and sh Foods associated with the emetic type of poisoning include rice products potato pasta and cheese products Other foods such as sauces pastries soups puddings and salads were identi ed as vehicles in food poisoning outbreaks Table 5 Food samples positive for B cereus Food Sample Percent Positive Pork 47 Beef 1 1763 Chicken 077 Meat additives 39 Raw milk 9 Pasteurized milk 3 5 Dairy products 0763 Raw rice 100 Pasta and our 0 Seafood 1 Infective Dose The infective dose of B cereus ranges from 104 to 1011 cells per gram of food This is dependent on a number of factors including the presence of viable cells or spores in the food the amounts of enterotoxins produced and the susceptibility of target population Target Populations It is believed that all individuals are susceptible to B cereus food poisoning but more severe symptoms have been associated with young adults and the elderly Detection of B cereus 250H6 6 Refer to the Compendium of Methods for the Microbiological Examination of Foods Blood agar can be used as a plating medium Nutrient broth followed by blood agar useful for most probable number count Prevention Since B cereus is 39 39 J quot in the 39 I quot contamination of food with its spores is almost impossible Thus measures to inhibit spore germination and prevent the growth of vegetative cells in cooked readytoeat foods might be the approach to effectively prevent and control the spread of this pathogen Thorough cooking is most likely to destroy the vegetative cells and spores However temperatures under 100 C 212 F might allow spore survival Nonrefrigerated storage of foods and especially rice should be avoided Also foods that require heating or cooling should undergo that process rapidly References Gilbert R J 1979 Bacillus cereus pp 4957514 In H Riemann and FL Bryan eds Foodbome Infections and Intoxications 2quotd ed Academic Press New York NY Grif ths MW and Schraft H 2002 Bacillus cereus food poisoning pp 2617270111 Cliver DO and Riemann HP eds Foodbome Diseases 2quotd ed Academic Press New York NY Schraft H and Griffiths MW 2006 Bacillus cereusgastroenteritis pp 5617582 In H Riemann and DO Cliver eds Foodbome Infections and Intoxications 3rd ed Academic Press New York NY Wijnands LM Dufrenne JB Zwietering MH van Leusden FM 2006 Spores from mesophilic Bacillus cereus strains germinate better and grow faster in simulated gastrointestinal conditions than spores from psychrotrophic strains International Journal of Food Microbiology 112 1207128
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