Food Toxicology 2(2+0)

Lesson 11 : Toxicants Found in Foods

Bacteria that cause food borne illness and infections

Infections

Campylobacter jejuni	Intestinal tracts of animals and birds, raw milk, untreated water, and sewage sludge.	Contaminated water, raw milk, and raw or undercooked meat, poultry, or shellfish.	Fever, headache and muscle pain followed by diarrhea (sometimes bloody), abdominal pain, and nausea that appear 2 to 5 days after eating; may last 7 to 10 days.
Clostridium perfringens	Soil, dust, sewage, and intestinal tracts of animals and humans. Grows only in little or no oxygen.	Called “the cafeteria germ” because many outbreaks result from food left for long periods in steam tables or at room temperature. Bacteria destroyed by cooking, but some toxin-producing spores may survive.	Diarrhea and gas pains may appear 8 to 24hours after eating; usually last about 1day, but less severe symptoms may persist for 1 to 2 weeks
Escherichia coli O157:H7	Intestinal tracts of some mammals, raw milk, unchlorinated water; one of several strains of E. coli than can cause human illness.	Contaminated water, raw milk, raw or rare ground beef, unpasteurized apple juice or cider, uncooked fruits and vegetables; persons-to-person.	Diarrhea or bloody diarrhea, abdominal cramps, nausea, and malaise; can begin 2 to 5 days after food is eaten, lasting about 8days. Some, especially the very young, have developed hemolytic-uremic syndrome (HUS) that causes acute kidney failure. A similar illness, thrombotic thrombocytopenic purpura (TTP), may occur in adults.
Listeria monocytogenes	Intestinal tracts of human and animals, milk, soil, leaf vegetables; can grow slowly at refrigerator temperatures.	Ready-to-eat foods such as hot dogs, luncheon meats, cold cuts, fermented or dry sausage, and other deli-style meat and poultry, soft cheeses and unpasteurized milk.	Fever, chills, headache, backache, sometimes upset stomach, abdominal pain and diarrhea; may take up to 3 weeks to become ill; may later develop more serious illness in at-risk patients (pregnant women and newborns, older adults, and people with weakened immune systems).
Salmonella (over 2300 types)	Intestinal tracts and feces of animals; salmonella enteritidis in eggs.	Raw or undercooked eggs, poultry, and meat; raw milk and dairy products; seafood, and food handlers.	Stomach pain, diarrhea, nausea, chills, fever, and headache usually appear 8 to 72 hours after eating; may last 1 to 2 days.
Shigella (over 30 types)	Human intestinal tract; rarely found in other animals.	Person-to-person by fecal-oral route; fecal contamination of food and water. Most outbreaks result from food, especially salads, prepared and handled by workers using poor personal hygiene.	Disease referred to as “shigellosis” or bacillary dysentery. Diarrhea containing blood and mucus, fever, abdominal cramps, chills, and vomiting; 12 to 50 hours from ingestion of bacteria; can last a few days to 2 weeks.
Vibrio	Cholera is the disease associated with the organism and the responsible toxicant is cholera toxin (choleragen). The organism can exist in saltwater for long periods of time and is found in plankton and shellfish.	Transmission is by ingesting uncooked or undercooked seafood or by the fecal–oral route. The contaminated food must be boiled for a least 10 min to inactivate the organism.	Between several hours and a few days, patients experience an explosive onset of watery diarrhea, vomiting, and abdominal pain. Fluid output can be voluminous, with up to 20 to 30 evacuations. The intestinal mucosa becomes shredded with damage, releasing plugs of mucus from intestinal cells resembling grains of rice (rice-water stools). Mortality can be less than 1% if fluid replacement treatment is initiated; if untreated, 60% of the patients can become comatose and die.

Chemical food poisoning results from eating a plant or animal that contains a toxin

• The poisoning occurs after ingesting poisonous species of mushrooms or plants or contaminated fish or shellfish.
• The most common symptoms are diarrhea, nausea, and vomiting and sometimes seizures and paralysis.
• The diagnosis is based on symptoms and examination of the ingested substance.
• Avoiding wild or unfamiliar mushrooms and plants and contaminated fish reduces the risk of poisoning.
• Replacing fluids and ridding the stomach of the toxic substance are the best forms of treatment; however, some substances are deadly.