FDSCI 600 8/25, 8/27, and Recitation Notes
FDSCI 600 8/25, 8/27, and Recitation Notes 600
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This 8 page Class Notes was uploaded by . Notetaker on Sunday August 30, 2015. The Class Notes belongs to 600 at Kansas State University taught by Dr. Sara Gregg in Summer 2015. Since its upload, it has received 165 views. For similar materials see Food Microbiology in Child and Family Studies at Kansas State University.
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Date Created: 08/30/15
FDSCI 600 Intro Lecture 82515 VI VII What is food micro The study of microbes that grow in food and how environments in uence microbes a Emphasis on bacteria because less is known about viruses and bacteria Why do we care a Some microbes are our friend Ex fermentations lactic acid bacteria yogurt shelfstable sausage yeasts bread beer b Foodborne illnesses cause 48 million sicknesses each year Gregg says you do not need to know statistics for the exam c Our food supply i 13 is lost to spoilage ii 13 of world worries about nutrition demand on safer food iii Zero risk is impossible why There are so many quotbugsquot microbes with many mutations people react differently to each of them Morphology a Rod shaped bacilli b Spherical cocci c Chains streptococcus d Clusters staphylococcus Gram Positive Bacteria a Cell was composed of peptidoglycan i Repeating polymer of Nacetylglucosamine ii Nacetylmuramic acid iii Linked together b peptide bonds iv Stains PURPLE b Structure i On the outside they have teichoic acids responsible for immune response 1 Antigens on the teichoic acid 2 Somatic cellular 0 antigen causes immune response ii Cell wall on the outside contains peptidoglycan iii Cell membrane inner Gram Negative Bacteria a Outer membrane composed of lippolysaccharide i LPS responsible for immune response 0 antigen ii STAINS PINK b Very little peptidoglycan c Inner membrane d Periplasm in between inner membrane and outer membrane Serology of Bacteria based on recognition of antigens on bacterium a By speci c antiserum antibodies b Different types of antigens on surface somatic c H antigens agellar i Polar agellum agellum on one side of bacteria ii Peritrichous agellum agellum on all sides of bacteria d K antigens capsular i Capsule produce by spoilage organisms slimy meat Microbial growth curve V Lerhrpqpop Y axis growth X axis Time First phase is lag phase microbes are not growing in numbers Log phase exponential microbial numbers increase drastically Stationary phase after the log phase microbe numbers plateau Death phase microbes die Be able to know this chart What is a good intervention in food science TO EXTEND THE LAG PHASE Food as ecosystems a Environment amp organisms that live in it i Intrinsic factors 1 pH a log scale measurement of acidity b do not need to know the pH equation c the lower the pH the more energy the cell must use d maintain intracellular pH near neutrality pH of 7 i results in less energy to grow produce toxins ii MAIN POINT pH is really good for controlling microbes Also in uences bacterial gene expression i Proton transport ii Amino acid degradation iii Adaption to acidic or basic conditions iv Virulence how the microbe evades the host immune system 2 water activity aw a refers to availability of water can inhibit microbes b Aw PPo i P vapor pressure of water in food ii Po vapor pressure of pure water at same temp c Microbes have different water requirements d When water concentration decreases lag phase of growth increases growth rate decreases and decreases the number of cells in stationary phase 3 nutrients ii extrinsic factors external to food 1 temperature a effects on growth rate amp gene expression b ex microbes grown at refrigerator temp grow more slowly have different genes and are physiologically different than those at room temp c types of microbes i psychrophile 15C optimum temp cannot grow at 30C ii psychrotroph gt20C optimum temp can grow at 20C D iii mesophile 2045C optimum temp iv thermophile65C optimum temp 2 gaseous environment a aerobic growth in oxygen b anaerobic growth in absence of oxygen c microaerophilic growth in atmosphere of reduced oxygen 35 oxygen 210 C02 d facultative microbes that prefer one type of atmosphere but can grow in multiple atmospheres 3 presence of other bacteria IX hurdle technology prevent growth of foodborne pathogens limit Aw to lt85 OR pH to 46 a utilizes multiple factors to control spoilage organisms amp foodborne pathogens X quorum sensing bacterial communication celldensity dependent a regulates gene advantages to larger populations i autoinducers microbial signals they are cell density dependent ii low bacterial population low signal and vise versa b effect of food molecules on quorum sensing i mimic or alter signaling systems why is this important Can mimic spoilage or pathogenic microbes c up regulation of genes often increases virulence of pathogen that overwhelms the host d BIOFILMS is sometimes the result of quorum sensing i It39s the aggregation of many species coming together to form complex structures on solid surfaces 1 Exopolysaccharide EPS produced by cells a Triggered by quorum sensing b Anchors cells to surface 2 Microcolonies form channels form throughout bio lm brings in nutrients 3 Highly resistant to heat chemicals sanitizers antibiotics BAD FOR FOOD MICROBIOLOGY FDSCI 600 Lecture 2 Regulation I Food regulation a USDA amp FDA both emphasize food safety concern i Emphasis is put on biological hazards chemical hazards are of some concern but not as much as biological b USDA i Mission food agriculture natural resources related issues ii 7 mission areas food safety food nutrition amp consumer 1 17 agencies 71 in book a Food safety and inspection service FSIS works to protect public from food borne illness inspect meats poultry amp egg products i Responsible for safety and labeling ii FDA regulates game meats ostrich snake etc iii Began under Federal Meat Inspection Act 1 Because of bookJungle exposed meat packaging industry unethical and unsanitary practices 2 Developed sanitary requirements amp inspchons Pathogen reductionHACCP system provides framework for regulations within USDA Agricultural research service in house research branch i Ex clay center Nebraska US meat research center c FDA under health amp human services Responsible for foods are safe wholesome and sanitary 1 Regulates safety amp labeling NO MEAT POULTRY amp ALCOHOL 2 Regulates vet drugs biological produces cosmetics livestock amp pet food 3 Makes sure products are produced honestly accurately informatively represented to the consumer Came to be because of the food amp drugs act again by the book Jungle 1 Food drug amp cosmetic act 1938 2 Food safety modernization act 2010 signed by Obama a b lntent emphasis on prevention of food safety issues in food supply Sciencebased standards in effect to insure safe production of fruits veggies and transportation i Guidance documents all documents that provide guidances to how should transport quotshouldquot be happening they are now laws Riskbased inspection required to be inspected within 5 years of law inactment no less than 3 years after Food importers enhanced ability to oversee whats coming in d Recall authority i USDA has no legal authority to initiate recall they can quotsuggestquot to companies 1 FSIS can detain amp seize products if recall is refused ii FDA has authority to issue mandatory recalls e CDC centers for disease control and prevention branch of health amp human services i NOT regulatory oversees survailance of foodborne illness outbreaks ii Enhanced detection amp tracking unknown diseases identify sources 1 Works together with FDA amp USDA iii Surveillance 1 Outbreak de nition 2 or more cases of a similar illness result from the ingestion of a common food a Foodborne diseases active surveillance of the following organisms i Campylobacter cryptosporidium cyclospora listeria salmonella Escherichia coli shigella vibrio Yersinia b FoodNet organization that does the surveillance reporting iii Objectives determine the burden of illness in US 1 Monitor trends 2 Attribute burden to speci c food amp settings 3 Assess interventions to reduce foodborne illness iv ACTIVE surveillance health agencies regularly contact the physicians and labs to attain data v PASSIVE surveillance health agencies are contacted by the physicians and labs iv Foodborne outbreak local state or national 1 Usually picked up local health department noti ed a Report ill persons amp physicians 2 State health department will then start initiating investigated using gel electrophoresis PFGE determines a ngerprint of the microorganisms a Ex Salmonella can be isolated from many patients and all will have the same ngerprint b Fingerprints uploaded into PulseNet amp PulseNet International 3 Investigation stages a Epidemiological study of incidence distribution and control of disease in population i Increase in lab testing Illness reporting iii Other surveillance iv Issues that hinder epidemiology 1 Underreporting of illnesses 2 Personperson transmissionanimal contact a When people question you you never consumed the product 3 Actively search for cases demographics clinical symptoms identifying risk factors b Laboratory i Microbiologists identify cause sample analysis 1 Causative agent in sample 2 Sample from unopened food product 3 Match with PFGE c Environmental i Local board of health ii Objectives 1 work to identify of reason or source 2 initiate corrective actions a contaminated foods b poor foodhandling practices that led to contamination 3 within 2448 hours of foodborne illness complaint 4 use lab results and epi Findings 5 investigation locations a document all contamination of pathogens tractor tables 6 problems a wide distribution areas b long shelf lives of foods d agroterrorism i food security includes food safety ii public health security and bioterrorism preparedness and response act of 2002 iii FDA counterterrorism efforts 1 Threat assessment tip given to agency 2 Surveillance no improper acts 3 Deterrence amp prevention 4 Containment through rapid release e Global food safety i Codex alimentrius food amp agriculture organization of the UN 1 WHO ii Global harmonization initiative 1 Global harmonization of food safety regulationslegislation 82715 Recitation on Regulatory Issues amp lntro section VI Does FSMA base their regulations on scienti c data YES a Does not control meatpoultry b Most focused on product FDA so many jurisdictions that they oversee electronics cosmetics they are overwhelmed a FSMA relies on localstate level officials to oversee most food b Have legal action on mandate authority USDA can only quotsuggestquot FSIS can detain and seize products i FDA can pull registration from companies Whole genome sequencing more quottrendyquot way to ngerprint microorganisms Laboratory practices has to be from unopened food product Why To make sure its not contaminated by the person or by other means Why might it be hard for an environmental investigation a The eld has already been plowed under could nd soil sample lntro notes a Bacterial cell morphology is important Know this for exam As well as gram and gram be able to tell the differences i Know the different antigens on bacteria th Microbial growth curve important i Good intervention extends the lag phase Important of water although a certain microorganism cant grow at a certain water concentration they can still survive Understand the temperature differences in micrboes psychrophile mesophile etc i Know the extrinsic factors aerobic anaerobic etc Hurdle technology prevents growth of foodborne pathogens Quorum sensing bacteria can communicate with same species and other species to form bio lms i Bio lms are important because they are more virulent and are able to withstand heat pH water deprivation many of the things that usually kill the bacteria
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