Colorado State University Extension
SafeFood Rapid Response Network
SAFEFOOD NEWS - Winter/Spring 1999 - Vol 3 / No. 2
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Listeriosis and Food Safety Recommendations
Listeriosis is an illness caused by eating foods contaminated with Listeria monocytogenes. L. monocytogenes is found in soil, leaf litter, sewage, silage, dust, and water and can contaminate a variety of raw foods, such as uncooked meats and vegetables. Foods can also become contaminated after processing; examples are soft cheeses, hot dogs, and luncheon meats.
L. monocytogenes is a hardy bug. It is slightly more heat resistant than other bacteria and will grow at temperatures as high as 140-150 degrees F; however, it will not survive pasteurization or heat treatment. This bacteria can even multiply slowly at 34 degrees F.
What populations are at greatest risk?
- Pregnant women and newborns
- Older adults
- People with immune systems that are weakened (e.g., people who have chronic illnesses, such as diabetes, kidney disease, cancer, and AIDS)
What are the symptoms?
- Flu-like symptoms such as fever and chills
- Sometimes upset stomach
- Note that it can take up to 8 weeks for a person to become sick after eating food contaminated with L. monocytogenes.
- Infected pregnant women may experience mild flu-like symptoms, but the illness can be transmitted to the fetus which may result in a spontaneous abortion or stillbirth.
To reduce the risk, the USDA recommends that at-risk consumers, and people who prepare their food should:
- Reheat until steaming hot the following types of ready-to-eat foods: hot dogs, luncheon meats, deli meats, cold cuts, fermented and dry sausage, and meat and poultry products. If you cannot reheat these foods, it's best not to eat them at all.
- Wash hands with warm, soapy water after handling raw foods and the above types of ready-to-eat foods. (Wash for at least 20 seconds.) Also wash cutting boards, dishes, and utensils. Thorough washing helps eliminate any bacteria that might get on your hands or other surfaces from food before it's been cooked or reheated.
- Don't eat soft cheeses such as feta, Brie, Camembert, blue-veined varieties, or Mexican-style cheese. At-risk consumers can eat hard cheeses, processed cheeses, cream cheese, cottage cheese, and yogurt.
- Do not drink raw, unpasteurized milk or eat foods made from it, such as unpasteurized cheese.
- Observe all expiration dates for perishable items that are precooked or ready-to-eat.
Sources: 1) FSIS Action Plan for Addressing Listeria monocytogenes, Backgrounders, May 1999, FSIS. USDA. 2) Listeria monocytogenes, Bad Bug Book, USFDA, CFSAN, 1992. 3) USDA Recommends Safeguards for Consumers at Increased Risk for Listeriosis, FSIS, May 1999.
Updated Monday, August 29, 2011
