Unlike most other bacteria, Listeria multiplies at refrigerator temperatures. Listeria can also grow on soft cheeses during their ripening period. The average time period between exposure and symptoms is thought to be 3 weeks, but can range from 3 to 70 days. Persons who are ill should see their health care provider. Stool cultures are not recommended, but your physician may culture your blood to determine if you have listeriosis.
Specific treatment consists of antibiotics.
Penicillin or ampicillin alone, or together with other antibiotics may be prescribed by your health care provider. Pregnant women, immunocompromised persons, the chronically ill and the elderly, should eat only thoroughly cooked meats and seafood and pasteurized dairy products. Hard cheeses, processed cheeses, cream cheese, cottage cheese, or yogurt need not be avoided. These persons may choose to avoid or to thoroughly cook summer sausage, hot dogs and luncheon or deli meats. Wash your hands thoroughly after handling raw meat, contact with animals and gardening.