Causes

Listeria bacteria can be found in soil, water and animal feces. People can get infected by eating the following:

• Raw vegetables that have been contaminated from the soil or from contaminated manure used as fertilizer
• Contaminated meat
• Unpasteurized milk or foods made with unpasteurized milk
• Certain processed foods — such as soft cheeses, hot dogs and deli meats that have been contaminated after processing

Unborn babies can contract a listeria infection from the mother.