Listeria: Risks, Treatment, and Prevention During Pregnancy
During pregnancy, it is important to be aware of what you put inside your body. You should be aware of what is good to eat and also what is not so good to eat. Listeria is a type of bacteria that can be found in some contaminated foods. Listeria can cause problems for both you and your baby. Although listeriosis (the illness from ingesting Listeria) is rare, pregnant women are more susceptible to it than non-pregnant healthy adults.
What is Listeria?
Listeria monocytogenes is a type of bacteria that is found in water and soil. Vegetables can become contaminated from the soil, and animals can also be carriers. Listeria has been found in uncooked meats, uncooked vegetables, unpasteurized milk, foods made from unpasteurized milk, and processed foods. Listeria is killed by pasteurization and cooking. There is a chance that contamination may occur in ready-to-eat foods such as hot dogs and deli meats because contamination may occur after cooking and before packaging.1
What are the risks of a pregnant woman getting listeriosis?
According to the Center for Disease Control (CDC), an estimated 1,700 persons become seriously ill each year in the United States and among these, 260 will die. Although the CDC states that pregnant women are 20 times more likely to become infected than non-pregnant healthy adults, the number of cases of listeriosis in pregnant women is about 17%.
How will I know if I have listeriosis?
Symptoms of listeriosis may show up 2-30 days after exposure. Symptoms in pregnant women include mild flu-like symptoms, headaches, muscle aches, fever, nausea, and vomiting. If the infection spreads to the nervous system it can cause a stiff neck, disorientation, or convulsions. Infection can occur at any time during pregnancy, but it is most common during the third trimester when your immune system is somewhat suppressed. Be sure to contact your health care provider if you experience any of these symptoms. A blood test can confirm an infection from listeriosis.
Will this harm my baby?
If you are pregnant and are infected with listeriosis, you are at an increased risk of :
- Premature delivery
- Infection to the newborn
- Death to the newborn (about 22% of cases of perinatal listeriosis result in stillbirth or neonatal death)
Early treatment with antibiotics may prevent fetal infection and other severe fetal complications. Not all babies whose mothers are infected will have any problems related to listeriosis.
How is it treated?
Listeriosis is treated with antibiotics during pregnancy. These antibiotics, in most cases, will prevent infection to the fetus and newborn. These same antibiotics are also given to newborns with listeriosis.
What can I do to protect my baby from listeriosis?
Following these guidelines can greatly reduce your chances of contracting Listeriosis:
- Eat hard cheeses instead of soft cheeses: The CDC has recommended that pregnant women avoid soft cheeses such as feta, Brie, Camembert, blue-veined cheeses and Mexican style cheeses such as queso fresco, queso blanco, and panela that do not state they are pasteurized. Hard cheeses such as cheddar and semi-soft cheeses such as mozzarella are safe to consume. Pasteurized processed cheese slices and spreads such as cream cheese and cottage cheese can also be safely consumed. The most important thing to do is to read the labels!
- Be cautious when eating hot dogs, luncheon meats, or deli meats unless they are properly reheated to steaming (or 160 degrees F.): Eating out at certain restaurants that provide deli meat sandwiches is not recommended for pregnant women since they do not reheat their deli meats. Restaurants such as Subway recommends that pregnant women eat the following non-luncheon meat items such as meatball, steak and cheese, roasted chicken, and tuna (limit 2 servings a week).
- Do not eat refrigerated pates or meat spreads.
- Do not eat refrigerated smoked seafood unless it is contained in a cooked dish, such as a casserole.
Practice safe food handling:
- Wash all fruits and vegetables
- Keep everything clean including your hands and preparation surfaces
- Keep your refrigerator thermometer at 40 degrees or below
- Clean your refrigerator often
- Avoid cross-contamination between raw and uncooked foods (this includes hot dog juices)
- Cook foods at proper temperatures (use food thermometers) and reheat all foods until they are steaming hot (or 160 F)
Proper Temperatures for Cooking Foods:
- Chicken: 165-180 F
- Egg Dishes: 160 F
- Ground Meat: 160-165 F
- Beef, Medium well: 160 F
- Beef, Well Done: 170 F (not recommended to eat any meat cooked rare)
- Pork: 160-170 F
- Ham (raw): 160 F
- Ham (precooked): 140 F
Refrigerate or freeze food promptly.
For more information on food safety and prevention of food-borne illnesses such as listeria you can contact:
Centers for Disease Control and Prevention/Foodborne Illness Line
(24 hr recorded information)
U.S. Food and Drug Administration Center for Food Safety & Applied Nutrition
Last updated: October 10, 2019 at 14:19 pm
Compiled using information from the following sources:
1. Centers for Disease Control and Prevention
2. Williams Obstetrics Twenty-Second Ed. Cunningham, F. Gary, et al, Ch. 58
3. Organization of Teratology Information Specialists, OTIS.