What to know about listeria

Have you ever eaten something and felt not quite right afterwards? Although it’s hard to say for sure, that feeling might have been caused by something you ate—maybe a type of food poisoning.

Many people don't realize that they have food poisoning because the symptoms can be mild or very similar to the stomach flu. But when you're pregnant, certain types of food poisoning, such as a listeria infection, can be very serious.

What is listeria and where is it found?

Listeria (Listeria monocytogenes) is a bacteria that can be found in soil, water and animals. Because of that, listeria can enter the food supply during the growing or manufacturing process. It's also found in some foods after processing and before packaging. The foods that might contain listeria include:

• Unwashed raw vegetables
• Raw meat and meat products
• Unpasteurized milk or foods made with unpasteurized milk, such as soft cheeses
• Hot dogs and deli meats
• Refrigerated pate or meat spreads from a store deli or meat counter
• Smoked seafood from the refrigerated section of a store
• Deli salads, such as chicken, ham, egg, tuna or seafood salad

Symptoms and treatment

If a pregnant woman has a listeria infection (listeriosis) symptoms can be so mild that she may not even realize it. Or the symptoms can mimic the flu and include fever, chills, muscle aches, upset stomach and diarrhea. If not treated, symptoms can progress to include a stiff neck and headaches.

If you think you have listeriosis, your health care provider may recommend a blood test to be sure.

Helping to prevent listeria infections

The best way to help prevent a listeria infection is to avoid eating the foods that are most at risk for having the bacteria (see list above). You can also heat certain high-risk foods to kill any listeria that might be present. Here are some other tips for minimizing your exposure to listeria:

• Always fully cook meat, poultry and fish
• Heat hot dogs and deli meats to 165 degrees F before eating
• Eat only cheeses clearly labeled “made with pasteurized milk”
• Wash raw vegetables before eating or cooking them
• Wash your hands thoroughly after handling raw meat, poultry, seafood and hot dogs
• If juices from meat, poultry or hotdogs spill on counters or in the refrigerator, clean them up immediately and wash your hands well
• Keep your refrigerator at or below 40 degrees F to limit bacterial growth

When to see your health care provider

If you think you might have the symptoms of a listeria infection, contact your health care provider. If you think that you may have eaten something that was contaminated with listeria and have a fever or symptoms of a serious illness within two months of eating that food, see your health care provider.

Learn more about foods to avoid during pregnancy.