If you're considered at risk, avoid high-risk foods and handling food properly.
Thoroughly cook raw food from animal sources, such as beef, pork or poultry to a safe internal temperature.
Rinse raw vegetables thorougly under running water before eating.
Keep uncooked meats and poultry separate from vegetables and from cooked foods and ready-to-eat foods.
Do not drink raw and unpasteurized milk and do not eat foods that have unpasteurized milk in them.
Wash hands, utensils, countertops and cutting boards after handling and preparing uncooked foods.
Consume perishable and ready-to-eat foods as soon as possible.
Be aware that Listeria can grow in foods in the refrigerator.
Clean up spills in your refrigerator right away.
Clean the inside walls and shelves of your refrigerator with hot water and liquid soap and then rinse.
Divide leftovers into shallow containers for fast, even cooling.
ABC News affiliate KMGH-TV and The Associated Press contribute to this story.