Organisms Associated with Foodborne Illness

Hilary Shallo Thesmar, Ph.D., R.D.

Many people have experienced some type of foodborne illness at some point in their life. When the symptoms first appear, most people think, "What did I eat at my most recent meal?" Did you know that most people do not feel ill until 2-7 days later, sometimes weeks after eating the contaminated food? There are a few organisms that cause illness within a few hours, but most take a day or more to cause symptoms.

There are two ways that organisms can cause illness, infection and intoxication. Infection is caused by the organism entering the body and growing. The organisms can be bacteria, viruses or parasites. Intoxication is caused by toxins or poisons that the organisms produce either in the food or once in the body.

Below is a table of organisms or toxins in foods that cause illness in humans and the associated symptoms and time until symptoms occur. The foods that are commonly associated with these organisms are in the last column. This is based on historical data from the CDC and only applies to contaminated foods. Most food is very safe and free of disease causing organisms if handled, stored and cooked properly.

What can you do to help reduce your chances of becoming ill?

Wash hands before preparing or touching any food
Cook food properly (use food thermometers)
Refrigerate foods to less than 40 °F. Use a refrigerator thermometer to make sure your refrigerator is cold enough.
Keep raw and cooked food separate (don’t let raw meat or anything that touches raw meat come in contact with food that is ready to eat such as a salad, fruit or bread)
Replace sponges and wash towels often
Clean counter tops, utensils and cutting boards thoroughly
Clean out refrigerator frequently. Discard old food and check expiration dates on packaged items.
"When in doubt, throw it out!"

Organism or toxin	Time for symptoms to appear	Symptoms	Associated foods
Staphylococcus aureus toxin	1-6 hours	Nausea Vomiting, diarrhea, abdominal pain	Foods that require considerable handling during preparation and that are kept at slightly elevated temperatures after preparation (salads, cream pastries). S. aureus produces a toxin that is not destroyed by heat, so be sure to discard foods that have been at room tempetature for 2 hours or more.
Clostridium perfringens	2 to 36 hours (usually 6-12 hours)	Abdominal cramps, diarrhea, sometimes nausea and vomiting	Temperature abused prepared foods, Meats, meat products, and gravy
Salmonella species	12 to 74 hours (usually 18 to 36 hours)	Abdominal cramps, diarrhea, vomiting, fever, chills, nausea, headache.	Raw meats, poultry, eggs, milk and dairy products, fish, shrimp, frog legs, yeast, coconut, sauces and salad dressing, cake mixes, cream-filled desserts and toppings, dried gelatin, peanut butter, cocoa, chocolate and nuts
E. coli	12-74 h, mean 18-36 h	Severe bloody diarrhea and abdominal cramps; nonbloody diarrhea, little or no fever	Undercooked contaminated ground beef, raw milk or juice, contaminated water, sprouts, or lettuce
Campylobacter	2 to 5 days, illness lasts 7-10 days with relapses	Diarrhea, fever, abdominal pain, nausea, headache and muscle pain	Raw or undercooked chicken, raw milk, contaminated water
Listeria monocytogenes	48 to 72 hours but up to 30 days	Fever, headache, nausea, vomiting	Soft cheese, unpasteurized milk, deli meats, hot dogs, refrigerated foods
Norwalk virus, Norwalk-like virus	24-48 h , illness lasts for 24-60 hours	Mild illness with nausea, vomiting, diarrhea, and abdominal pain. Headache and low-grade fever may occur	Contaminated water, shellfish Improper hygiene and food handling is a frequent cause

Table adapted from FDA Bad Bug Book www.cfsan.fda.gov/~mow/intro.html

And Partnership for Food Safety Education www.fightbac.org

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