Listeriosis is a disease caused by eating food contaminated with the bacterium Listeria monocytogenes.

Disease Fact Sheet

Disease Facts

  • 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.

You get listeriosis by eating food contaminated with Listeria. Babies can be born with listeriosis if their mothers eat contaminated food during pregnancy.

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.

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.

  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.
  1. 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.


This material is provided by the South Dakota Department of Health 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.

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