Listeriosis is a food-borne illness. It's caused by bacteria that may be in some foods. The listeria germs have been found in a variety of raw foods. These include uncooked meats, and raw unwashed fruits and vegetables. It may also be in processed foods that get contaminated after processing. These include hot dogs, soft cheeses, and cold cuts at the deli counter. Unpasteurized (raw) milk or foods made from raw milk may have the germs.

Infection happens after eating a contaminated food. It's most common during the third trimester of pregnancy. Women often have flu-like symptoms, such as fever, muscle aches, and sometimes nausea or diarrhea. Unborn and newborn babies are at highest risk from the infection. Listeriosis may cause infection in the amniotic membranes. This can lead to miscarriage, stillbirth, or severe infection in a newborn. Antibiotics are used to treat the infection.

The CDC advises these ways to help prevent listeriosis:

• Fully cook raw food from animal sources, such as beef, pork, or poultry.
• Wash raw vegetables fully before eating.
• Keep raw meats away from vegetables. Keep them away from cooked foods and ready-to-eat foods.
• Don't drink raw (unpasteurized) milk or eat foods made from raw milk.
• Wash hands, knives, and cutting boards after handling uncooked foods.
• Don't eat soft cheeses, such as feta, Brie, Camembert, blue-veined, or Mexican-style cheese. You can have hard cheeses, processed cheeses, cream cheese, cottage cheese, or yogurt.
• Cook leftover and ready-to-eat foods until steaming hot before eating. This includes foods such as hot dogs.
• If you're pregnant, consider not eating foods from deli counters. Or, fully heat cold cuts before you eat them.
• Don't eat refrigerated smoked seafood, such as lox or salmon. Don't eat refrigerated pate or meat spreads.