South Dakota Department of Health
Office of Disease Prevention - 605-773-3737 — (1-800-592-1861 in South Dakota only)
This material is provided for informational purposes only and is not a substitute
for medical care. We are not able to answer personal medical questions. Please see your
health care provider concerning appropriate care, treatment or other medical advice.
What is listeriosis?
Listeriosis is a disease caused by eating food contaminated with the bacterium Listeria monocytogenes.
Who is at greatest risk of getting listeriosis?
- Pregnant women and their unborn babies,
- Persons with weakened immune systems,
- Persons with cancer, diabetes, kidney disease or undergoing graft suppression therapy,
- Persons who take corticosteroid medications,
- The elderly.
Healthy adults and children occasionally get infected with Listeria, but they rarely become seriously ill.
How do you get listeriosis?
You get listeriosis by eating food contaminated with Listeria. Babies can be born with listeriosis if their mothers eat contaminated food during pregnancy.
What are the symptoms of listeriosis?
A person with listeriosis may have fever, muscle aches, and sometimes nausea or diarrhea. If infection spreads to the nervous system, headache, stiff neck, confusion, loss of balance, or convulsions can occur.
Pregnant women may experience a mild, flu-like illness; however, infections during pregnancy can lead to premature delivery, infection of the newborn, or even stillbirth.
How does Listeria get into food?
Listeria monocytogenes is widely distributed in nature. Vegetables can become contaminated from the soil or from manure used as fertilizer. Animals can carry the bacterium and can contaminate meat and dairy products. Listeria has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods, such as soft cheeses and cold cuts. Unpasteurized milk or foods made from unpasteurized milk may contain the bacterium. Listeria can grow at refrigerator temperatures.
Dietary Recommendations for People at Higher Risk of Listeriosis*
1. Foods to avoid include:
- Raw or unpasteurized milk, including goat milk.
- Soft cheeses (e.g., feta, goat, Brie, Camembert, Gorgonzola, blue-veined, and Mexican-style queso fresco cheese).
- Dairy products that contain unpasteurized milk.
- Foods from delicatessen counters (e.g., prepared salads, meats, cheeses) that have not been heated/reheated adequately.
- Refrigerated pâtés, other meat spreads, and refrigerated, smoked seafood that have not been heated/reheated adequately.
2. Ways to reduce risk include:
- Cook leftover or ready-to-eat foods (e.g., hot dogs) until steaming hot before eating (165°F).
- Wash raw vegetables.
- Wash hands, knives, utensils, and cutting boards after exposure to uncooked or ready-to-eat foods.
- Prevent contamination from fluids of uncooked meats, hot dogs, and packaging onto other foods or food preparation surfaces by keeping them separate from vegetables, uncooked foods, and ready-to-eat foods.
- Use a refrigerator thermometer to set the refrigerator temperature to 40°F or lower and the freezer temperature to 0°F or lower.
*Pregnant women, older adults, and people who are immunocompromised by illness or therapy are at higher risk of invasive listeriosis.