Food Pathogens

OVERVIEW Define Food borne Illness Identify common food pathogens that cause food borne illness: BacteriaVirusFungiParasites

Food Borne Illness Are syndromes acquired by the consumption of food contaminated by disease pathogens, microbial toxins, or poisonous chemical substances. These illnesses are frequently sub-classified as infections or intoxications.

Types of Foodborne Illnesses INFECTION: Caused by the ingestion of food containing pathogenic microorganisms (i.e. bacteria, virus or parasite) which must multiply with in the gastrointestinal tract, producing widespread inflammation INTOXICATION: Caused by bacteria that under favorable conditions have produced chemicals(toxins)

Microorganisms in Food BacteriaE.Coli

Bacteria Causing Infections Bacteria Causing Infections and intoxications: Salmonella (non-typhoid) Salmonella Typhoid Campylobacter E. coli O157:H7 Clostridium perfringens Listeria monocytogenes Shigella Staphylococcus Aureus Clostridium Botulinum Bacillus Cereus

Bacteria Causing Infections Salmonella (non-typhoid) Reservoir: Food-producing animals Transmission Associated with undercooked meats (especially poultry) eggs, raw milk, and contaminated (especially poultry) eggs, raw milk, and contaminated produce produce Incubation : ½ day - 1½ days Disease: Diarrhea and systemic infections Prevention: Avoidance of cross contamination of foods (especially poultry) (especially poultry)

Bacteria Causing Infections Salmonella typhi: Typhoid Reservoir: humans, carried in the bloodstream and intestinal tract intestinal tract Transmission: Eating or drinking food or water that have been handled by a person shedding the bacteria been handled by a person shedding the bacteria Disease: Fever up to 39° – 40° C Incubation: days to several weeks Prevention: Vaccination. Boil water for 1 minute

Bacteria Causing Infections Campylobacter (“Camp-ill-oh-bacter”) Reservoir: Animals – raw or undercooked poultry Transmission: Cross contamination from undercooked poultry and raw milk; also from direct contact with animals poultry and raw milk; also from direct contact with animals Disease: Diarrhea (+/- bloody), cramping Incubation period: usually days Prevention: Thoroughly cook all products. Prevent cross contamination by using separate cutting boards for poultry contamination by using separate cutting boards for poultry and other foods and other foods

Bacteria Causing Infections E. coli O157:H7 Reservoir: Animals i.e. cattle and deer Transmission: Associated with undercooked, contaminated ground beef ground beef Disease: Diarrhea (usually bloody), kidney failure, possibly death death Incubation: days Prevention: Cook all ground beef to an internal temperature of 68° C. of 68° C.

Bacteria Causing Infections Clostridium perfringens Reservoir: Spore found in animal and human intestines; soil. Associated with large cuts of meat (i.e., large roasts or turkeys) Associated with large cuts of meat (i.e., large roasts or turkeys) Transmission: Temperature abuse of prepared foods. Improperly handled leftovers handled leftovers Incubation period: hrs (about ½ day) Disease: Mainly diarrhea and abdominal pain Prevention: The spore is not destroyed by normal cooking. Thoroughly cook food. Reheat leftovers thoroughly to at least 74° C cook food. Reheat leftovers thoroughly to at least 74° C

Bacteria Causing Infections Listeria monocytogenes Reservoir: Soil and water Transmission: Unpasteurized dairy products, processed meats, and processed produce meats, and processed produce Incubation period: days to weeks, average of 7-30 days. Usually only a problem in very young or elderly people Usually only a problem in very young or elderly people Disease: Fever, aches, nausea or diarrhea Prevention: Cook all meat thoroughly, drink only pasteurized dairy products pasteurized dairy products

Bacteria Causing Infections Shigella Reservoir: Humans Transmission: Contaminated foods from a carrier who does not wash their hands then handles food that is not does not wash their hands then handles food that is not thoroughly cooked afterward thoroughly cooked afterward Disease: Diarrhea (often bloody) Incubation days Prevention: Basic food safety precaution

Bacteria Causing Intoxications Staphylococcus aureus (“Staph”) Reservoir: Human skin and nasal cavities-- found in foods that are handled a lot that are handled a lot Transmission: Must multiply in food to produce enough toxin to cause illness toxin to cause illness Disease: Mainly nausea and vomiting Incubation: Short; usually hours Prevention: Bacteria is killed by cooking, however the toxin is not destroyed by normal cooking is not destroyed by normal cooking

Bacteria Causing Intoxications Clostridium botulinum (“botulism”) Reservoir: Spores found in soil and water (ocean/lakes) Transmission: Associated with improperly canned foods and ground-harvested foods such as onions and garlic Disease: Toxin causes paralysis and death! Incubation period: ½ day to 3 days Prevention: Spore not destroyed by normal cooking, but botulinum toxin CAN be destroyed by very hot cooking (e.g., food temp of 176F for at least 10 min)

Bacteria Causing Intoxications Bacillus cereus Reservoir: Spores found in soil, vegetables, cereals, grains, raw and processed foods Transmission: Grain foods cooked and not cooled/stored properly Disease: Severe nausea and/or diarrhea Incubation period: 1-6 hours Prevention: Proper refrigeration after cooking

Bacteria that form spores can survive cooking The spore form does NOT make us sick…it’s the vegetative form that causes illness Spore forming bacteria are in their spore form when they are under adverse conditions i.e. too hot/cold When they are comfortable, they go back into their vegetative state and can grow to very high numbers They do NOT grow in their spore form Spore Forming Bacteria

Viruses

Microorganisms in Food: Viruses Viruses cause INFECTIONS. They CANNOT grow in foods. They aren’t living so they can’t make a toxin Food borne viruses are spread through human feces to food or water

Modes of Viral Transmission Irrigation and spraying water Sewage Polluted Water Poor Personal Hygiene Drinking Water

Virus Types Hepatitis A Hepatitis E Norwalk Virus

Viral Causing Infections Hepatitis A Reservoir: Humans shellfish, and salads are the most frequent sources of outbreaks frequent sources of outbreaks Transmission: Food handler prepares food with their bare hands after using the restroom and not washing their hands hands after using the restroom and not washing their hands Incubation Period: 2-6 weeks. Average 28 days Disease: Infects the liver. Nausea, vomiting, jaundice Prevention: Hepatitis A vaccine is the best protection. Wash your hands after using the bathroom, changing a diaper, your hands after using the bathroom, changing a diaper, and before preparing and eating food and before preparing and eating food

Hepatitis E Reservoir: Humans and certain types of monkeys Transmission: Fecal-oral route, fecal contamination of water water Incubation period: days Disease: similar to Hepatitis A (Liver) Prevention: proper hygiene, proper disposal of feces

Viral Causing Infections Norwalk-like Virus Reservoir: Humans are the only known reservoir. Water is the most common source of outbreaks i.e. seafood and salads Transmission: Through fecally contaminated food Incubation Period: Approximately hours Disease: Nausea, vomiting, diarrhea, and abdominal pain. Infects the lining of the intestines Prevention: Wash hands after toilet visits and before preparing or eating food. Cook all shellfish thoroughly. Wash raw vegetables before eating.

Microorganisms in Food: Parasites Giardia Lamblia

Causes Giardiasis- Illness usually last 1-2 weeks, with possible chronic cases. More prevalent in children, immunity possible after first infection. Associated foods: contaminated water, contaminated vegetables, and infected or infested food handlers.

Entamoeba Histolytica

Causes Amebiasis Infections may last for years with out without symptoms. Transmitted by fecally contaminated food and water, direct contact with dirty hands or objects, and sexual contact. Infection is common in areas of poor hygiene All are susceptible but immunodeficient people are at risk of a more severe form of the disease.

Cryptosporidium Parvum

Cryptosporidium parvum Causes Cryptosporidiosis In most healthy individuals watery diarrhea last 2-4 days, have been known to last 1-4 weeks. No known treatment for cryptosporidiosis, invasion of pulmonary system may be fatal. Associated with contaminated hands, higher in day cares, vegetables fertilized in manure, contaminated water.

Microorganisms in Food: Fungi Types of fungi in foods: Molds often grow on breads, pastries, jellies, and dairy products. They can damage stored grain, fruit and vegetables, and livestock feed, thereby causing serious financial loss to farmers. Prevention: Maintain dry, airy surroundings; by heat- radiation techniques in the processing of food; and by using fungicides.

Review Questions 1. What is the difference between intoxication and infection? 2. Incubation period for salmonella? 3. How can you prevent E. Coli? 4. Giardia Lamblia causes what? 5. Is botulism an intoxication or infection?

Questions??