FOS2001 Module 4 (Food-Borne Diseases)
FOS2001 Module 4 (Food-Borne Diseases) FOS 2001
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This 9 page Class Notes was uploaded by Haley Kairab on Thursday April 7, 2016. The Class Notes belongs to FOS 2001 at University of Florida taught by Dr. Agata Kowalewska in Spring 2016. Since its upload, it has received 15 views. For similar materials see Man's Food in Nutrition and Food Sciences at University of Florida.
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Date Created: 04/07/16
FOS2001 Module 4 FoodBorne Disease KEY TERMS: • Closed or "coded" dating Refers to the packing numbers that are decodable only to manufacturers; often found on nonperishable, shelfstable foods • Danger zone Range of temperatures between 40 F and 140 F at which foodborne bacteria will multiply most rapidly, increasing risk of a foodborne disease • Fecaltooral transmission The spread of pathogens by putting something in the mouth that has been in contact with infected stool • Gastroenteritis Inflammation of the stomach and intestines • GRAS (generally recognized as safe) A substance that is believed to be safe to consume based on a long history of use by humans or a substantial amount of research that documents its safety • GuillainBarre syndrome A condition that can result from a Campylobacter infection; causes the immune system to attack its own nerves, and can lead to temporary paralysis • Highpressure processing (HPP) A process that pasteurizes foods by exposing them to pulses of high pressure, which destroy the microorganisms • Host A living plant or animal that harbors a virus, allowing it to survive and reproduce • Irradiation Subjecting foods to a radiant energy source that kills pathogens by breaking up the cells’ DNA • Modified atmosphere packaging (MAP) A food preservation technique that changes the composition of the air surrounding the food in a package to extend its shelf life • MDG symptom complex Reactions such as numbness, burning sensation, facial pressure or tightness, chest pain, rapid heartbeat, and drowsiness that can occur in some individuals when they consume the food additive monosodium glutamate (MSG) • Nitrates (nitrites) Reactions such as numbness, burning sensation, facial pressure or tightness, chest pain, rapid heartbeat, and drowsiness that can occur in some individuals when they consume the food additive monosodium glutamate (MSG) • Norovirus The most common type of virus that causes foodborne illness; can cause gastroenteritis (the stomach flu) • Open dating Refers to the calendar dates typically found on perishable items that can be easily read by consumers • Parasites Organisms that live on or in another organism • Pasteurization The process of heating liquids or food at high temperatures to destroy foodborne pathogens • Retort canning The process of subjecting alreadycanned foods to an additional hightemperature heat source • Spores Hardy reproductive structures that are produced by certain bacteria; some can survive boiling temperatures • Sulfites Preservatives that help prevent foods from turning brown and inhibit growth of microbes • Toxins Poisons that can be produced by living organisms • Virus A microscopic organism composed of protein and DNA that can infect a host and cause illness Occurrence of FoodBourne Disease • The following terms are used to figure out how often food borne illnesses occur: ◦ Case: one individual illness ◦ Sporadic case: one illness unrelated to any other ◦ Outbreak: two or more related cases (often reported in the news) • Illnesses can come from food from home or public places ◦ 5% can go back to foods bought from the grocery store ◦ 15% occur at home ◦ 40% occur with foods from restaurants ◦ 40% occur from other unidentified substances • Some symptoms of foodborne disease are similar to other ailments making it hard to definitively blame food Bacteria in Food • Scientists identify harmful bacteria in food with the following techniques: ◦ Staining bacteria are stained with die and the resulting color identifies the structure of the cell wall and membrane, and helps the initial identification of the bacteria ◦ Biochemical testing helps identify the genus of the microorganism ◦ Serology the study of blood serum, and is used to identify if, or how, the immune system is reacting to bacteria ◦ Genetic testing the most specific and costly testing, and requires DNA mapping to distinguish one bacterium from another • Identifying which bacteria is responsible for specific diseases is important for things like treatment plans. The Salmonella Family • One of the most common bacteria found in food • Over 2,000 species of salmonella have been identified • Estimated to cause over 2 million foodborne illnesses ◦ Usually not lifethreatening, but estimated 5001,000 deaths per year • Most frequent cases associated with poultry and raw/uncooked eggs • Onset can be from 1224 hours after ingestion and lasts 410 days Causes of Food Contamination • Exposing food to contaminated water: Water can carry harmful organisms, especially if it is contaminated with human or animal fecal matter. One hypothesis as to why certain pathogens have been found in fruits and vegetables is that fecal matter from farm animals runs into streams, and the stream water is then used to irrigate crops. In addition, water used to wash food can be a source of contamination. • Poor personal hygiene: Common sense dictates that you wash your hands before preparing food. • Insufficient or uneven cooking: Most meat must be cooked thoroughly to eliminate harmful bacteria. • Slow cooling of cooked foods: Cooked foods, such as leftovers, should be cooled quickly, instead of leaving them out in the air for an extended length of time. • Temperature regulation: The danger zone in terms of cooking is between 40 and 140 degrees Fahrenheit. Hot foods should be kept hot (140 degrees or above) and cold foods should be kept cold (40 degrees or cooler). Anything in between is the danger zone in which microorganisms grow rapidly. Food left at temperatures between 40 and 140 degrees Fahrenheit for more than four hours is potentially at risk and should be discarded. • Crosscontamination: This occurs when raw food and cooked food share the same preparation and/or serving area. Putting cooked chicken back on the surface you used to prepare the raw chicken (without cleaning the surface) is an example of cross contamination. • Unsanitary preparation areas: Food preparation areas must be kept clean to avoid becoming hospitable environments for microorganisms. • Inadequate refrigeration: Refrigerators should be set to 40 degrees or below (but not low enough to freeze the food) to keep food out of the danger zone. • Improper thawing procedures: Thawing food by placing it on a countertop thaws only the outer surface and lets bacteria grow. Proper thawing can be accomplished by running water constantly over the item, or by keeping it refrigerated as it thaws. • Human error: This can result from either an inadvertent mistake, or a lack of education about proper food preparation procedures. Monitoring the Food Supply • Absolute food safety cannot be guaranteed, however: ◦ Food Safety Initiative (FSI) started in 1997 where several government agencies work together to safeguard America's food supply from foodborne illnesses • Centers for Disease Control and Prevention (CDC), The United States Department of Agriculture (USDA), and Food and Drug Administration (FDA) work together to identify and trace causes of foodborne illnesses as quickly as possible • The law states that all food can contain a limited amount of defects Escherichia Coli (E. Coli) • This type of bacteria resides in all animal intestines • Most are harmless but there are three that are harmful ◦ Enterotoxigenic produces a toxin in the gut that causes watery diarrhea ◦ Enteroinvasive penetrates the intestinal wall causing colitis (inflammation of colon) and dysentery ◦ Enterohemorrhagic combination of the first two, plus additional symptoms of hemorrhagic colitis (overtly bloody kind of diarrhea) and painful cramping • Infectious and easily spread • Most pathogens require millions of cells to do damage, but E. Coli if only 1 of 10 cells are present Vibrio Cholerae • The bacteria that causes cholera • Found in contaminated water or food; caused by unsanitary conditions • Expresses itself as extreme, watery diarrhea which causes dehydration (it is the dehydration that causes death) • Changed history more than any other disease because it has happened in huge epidemics • Can be defined by three types: ◦ Asymptomatic (no symptoms) ◦ Mild diarrhea ◦ Cholera gravis (a condition of dehydration and shock leads to the most deaths) • Ubiquitous in marine waters Listeria • Bacteria that causes listeriosis (a meningitis type of infection that attacks brain lining or septicemic, i.e. contributory to blood poisoning) • Grows even food that is refrigerated/frozen • Found in soil, water, air, and has a fairly high mortality rate ◦ Unborn fetuses have higher risk from this bacteria • Symptoms for healthy individuals: ◦ Fever, vomiting, malaise, diarrhea • Symptoms usually last 7 to 14 days longer for people in highrisk categories • Onset of the disease can happen from 370 days after ingestion ◦ Most reported incidents are reported 4872 hours after ingestion • An outbreak in 1985 showed how serious the effects could be ◦ The bacteria were found in a soft cheese that was sold commercially • Foods that are susceptible ◦ Cheese, seafood salads, readytoeat foods, smoked fish/meats, ice cream, raw vegetables Staphylococcus Aureus and Clostridium Botulinum • Staphylococcus Aureus a bacterium that produces a toxin ◦ More that 100,000 organisms per gram are needed for toxicity ◦ Symptoms: nausea, vomiting, abdominal cramping ◦ Onset is rapid and acute because you are ingesting the toxin ◦ Duration can last from 24 days and is serious ◦ Foods associated with it: poultry, meat, egg, bakery products, foods that are handled a lot • Clostridium Botulinum organism closely related with home canning preparations ◦ Usually referred to as botulism ◦ Bacterium that created a very potent neurotoxin, characterized by putting the body into paralysis ◦ Other symptoms: weakness, vertigo, double vision, blindness ◦ An anaerobic organism (grows well in foods that are packaged without oxygen) • Nonacidic foods and cooked foods that are then left out with no refrigeration are also susceptible ◦ The toxin is heatresistant • To destroy you must rigorously boil the entire food component food underwater for 15 minutes ◦ Incidence for botulism is very low but has high mortality rate Giardia, Cryptosporidium, and Cyclospora • These three types of organisms are eukaryotic cells they have a defined nucleus that has a nuclear structure • The Giardia organism ◦ Results in giardiasis which is very infectious ◦ Usually found in water, like streams in national/state parks ◦ Outbreaks are caused by animals defecating and excrement getting washed in to streams and food handlers not using proper hygiene • Cryptosporidium ◦ Another infectious disease present in water contaminated by animal fecal matter (usually cattle) ◦ Symptoms: severe diarrhea and coughing ◦ Onset is immediate and lasts for 24 days ◦ Can be serious for people with weakened immune systems • Cyclospora ◦ Relatively new to the U.S. originally thought to be only in Peru and Tibet ◦ Three outbreaks in Florida in 1995, 1996, 1998 ◦ Raspberries were the primary cause for the first two and the third was caused by contaminated lettuce ◦ Has no known hosts associated with it ◦ Research is still being done to determine how it spreads Hepatitis A and the Norwalk Agent • In addition to bacterial diseases, water or food contaminated by fecal matter can also lead to viruses • All viruses are parasites: need a living cell/host to function • Hepatitis A ◦ Virus that results when fecal matter is allowed to contaminate food or water which is then ingested ◦ Most humans are exposed to it in childhood and build up an immunity ◦ Has a long incubation period (1070 days) which is why is difficult to trace the source ◦ Most common symptom is jaundice ◦ Other symptoms (fever, malaise, nausea, anorexia) ◦ Treatment: those who are exposed to it take pooled gamma globulin to help immune system fight the virus • The Norwalk Agent ◦ Also caused by the fecaloral route of transmission ◦ Can be contracted by ingesting contaminated water or food ◦ It is thought to be second only to the common cold as an infectious agent ◦ In 1987, outbreaks occurred in Pennsylvania and Delaware that were traced to contaminated ice • Outbreaks have also occurred on cruise ships ◦ Symptoms: nausea, vomiting, diarrhea, cramping ◦ Poor food handling is suspecting of spreading the agent