Causes

Listeriosis

Choose a preferred language


What is listeriosis?

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 vegetables. It may also be in processed foods that get contaminated after processing. These include 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.


Preventing listeriosis

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.

Date Last Reviewed: 01/01/2024

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
user headset icon

Need Help? We're Here for You

Our Member Services team is here to help you understand your benefits, find care, or resolve concerns.

1-800-510-9132
quit smoking icon

Call NC Quitline

Need support to quit smoking, vaping, or to quit other nicotine products? You can receive support including medicines free of charge:

1-800-784-8669
car and bus icon

Schedule Transportation

Need transportation to a doctor's office, pharmacy, or other covered healthcare service? Contact us to arrange your ride.

1-800-510-9132
Stethoscope icon

Provider Directory

Need to find a provider like a Primary Care Physician, Specialist, OB/GYN, or a Psychiatrist? 

Provider Directory
Related Articles
Read article
OB/GYN
Fetal Monitoring

In pregnancy and during labor, your health care provider will check your unborn baby’s heart rate and other functions. Monitoring can be done on the outside of your belly (external monitoring). Or it may be done directly on the baby while inside your uterus (internal monitoring). Fetal monitoring is a very common procedure.

Read article
OB/GYN
Preterm Labor

Preterm labor is labor that starts before 37 completed weeks of pregnancy. Labor is when the uterus regularly tightens and the cervix starts to thin and open. This lets the baby (fetus) enter the birth canal.

Read article
OB/GYN
Completed Spontaneous Miscarriage

About 1 or 2 out of every 10 pregnancies end as miscarriages. Some end even before you know you are pregnant. This happens for a number of reasons, and usually the cause is never known.

Read article
OB/GYN
Cholestasis of Pregnancy

Cholestasis of pregnancy is a liver problem. It slows or stops the normal flow of bile from the gallbladder. This causes itching and yellowing of your skin, eyes, and mucous membranes. Cholestasis sometimes starts in early pregnancy. But it is more common in the second and third trimesters.