Listeriosis & Pregnancy: A Food Safety Concern

This information has been reviewed and adapted for use in South Carolina by P.H. Schmutz, HGIC Food Safety Specialist, and E.H. Hoyle, Extension Food Safety Specialist, Clemson University. (New 05/03.)

HGIC 3639

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When you're expecting, it's natural to be concerned about your health and that of your unborn baby. Maintaining a healthful diet, drinking plenty of liquids and taking prenatal vitamins are all important for the health of the expectant mother and her baby. Food safety is also very important. This information will help you make safe decisions when selecting and preparing food for yourself and/or your family.

What is Listeriosis?

Listeriosis is an illness caused by eating foods contaminated with a kind of bacteria, often found in soil and water, called Listeria monocytogenes. Most people do not get listeriosis. However, pregnant women and newborns, older adults, and people with weakened immune systems caused by cancer treatments, AIDS, diabetes or kidney disease, for example, are at risk for becoming seriously ill from eating foods that contain Listeria monocytogenes . The Centers for Disease Control and Prevention (CDC) estimates that 2,500 people in the United States become seriously ill from listeriosis each year. Of these, one in five die from the disease.

Why is Listeriosis Especially Dangerous for Pregnant Women and Their Babies?

Hormonal changes during pregnancy have an effect on the mother's immune system that leads to an increased susceptibility to listeriosis. According to the CDC, pregnant women are about 20 times more likely than other healthy adults to get listeriosis. In fact, about one-third of listeriosis cases happen during pregnancy. Listeriosis can be transmitted to the fetus through the placenta even if the mother is not showing signs of illness. This can lead to premature delivery, miscarriage, still-birth or serious health problems for her newborn.

What are the Symptoms of Listeriosis?

Because the symptoms of listeriosis can take a few days or even weeks to appear and can be mild, you may not even know you have it. This is why it's very important to take appropriate food safety precautions during pregnancy.

Listeriosis has flu-like symptoms, such as fever and chills. Sometimes the illness will cause an upset stomach, but not always. If the infection spreads to the nervous system, symptoms such as headache, stiff neck, confusion, loss of balance or convulsions can occur. While infected pregnant women may experience only mild, flu-like illness, the mother's illness can be transmitted to the fetus through the placenta with more serious problems for her baby.

It takes an average of three weeks for someone to become ill. If you are an at-risk individual and/or have symptoms that concern you, consult your physician. Listeriosis can be treated with antibiotics.

How can Listeriosis be Prevented?

Pregnant women and all at-risk consumers should follow this advice to prevent listeriosis:

• Do use all perishable items that are precooked or ready-to-eat as soon as possible.
• Do clean refrigerators regularly.
• Do use a refrigerator thermometer to make sure that the refrigerator always stays at 40º F or below.
• Do not eat hot dogs, luncheon meats or deli meats UNLESS they are reheated until steaming hot.
• Do not eat soft cheeses such as feta, Brie, Camembert, blue-veined cheeses, and Mexican-style cheeses such as queso blanco fresco. Cheeses that can be safely consumed include hard cheeses, semi-soft cheeses such as mozzarella, pasteurized processed cheese slices and spreads, cream cheese, and cottage cheese.
• Do not eat refrigerated pâté or meat spreads. Canned or shelf-stable pâté and meat spreads can be eaten.
• Do not drink raw (unpasteurized) milk or eat foods that contain unpasteurized milk.
• Do not eat refrigerated smoked seafood UNLESS it is an ingredient in a cooked dish such as a casserole. Canned fish, such as salmon and tuna, and shelf-stable smoked seafood may be safely eaten.

What Food Safety Steps Help Prevent Listeriosis and Other Foodborne Illnesses?

Follow these four simple steps to food safety:

• Clean: Wash hands and surfaces often with hot, soapy water. Because Listeria monocytogenes can slowly grow at refrigerator temperatures, always use hot, soapy water to clean up liquid that spills in the refrigerator - including spills from packages of luncheon meats and hot dogs. Always wash hands, cutting boards, dishes and utensils with hot, soapy water after they come in contact with raw food.
• Separate: Don't cross-contaminate. Raw meat, poultry and seafood can contain dangerous bacteria. As a result, keep these foods separate from vegetables, fruits, breads and other foods that are already prepared for eating.
• Cook: Cook to safe temperatures. If you are at risk for listeriosis, reheat luncheon meats, cold cuts, and other deli-style meat and poultry until they are steaming hot.
• Chill: Refrigerate or freeze perishables, including ready-to-eat foods, within two hours.

What Should You Do if You Have Food That is Recalled Because of Listeria monocytogenes?

Do not eat any food that is recalled and ordered off grocery store shelves. Return recalled food to the place where you bought it.

If you have eaten a contaminated product and do not have any symptoms, most experts believe you don't need any tests or treatment, even if you are pregnant. However, you should inform your physician or healthcare provider if you are pregnant and have eaten a contaminated product and experienced flu-like symptoms within two months.

For more information on food safety during pregnancy, request HGIC 3640, Food Safety for Pregnant Women & Their Babies.

Sources:

1. Food Safety and Inspection Service (2001, Sept.). Listeriosis and Pregnancy: What Is Your Risk? http://www.fsis.usda.gov/Fact_Sheets/Listeriosis_and_Pregnancy_What_is_Your_Risk/index.asp
2. FDA (2005, August). Food Safety for Moms-to-Be. Listeriosis: Frequently Asked Questions.http://www.cfsan.fda.gov/~pregnant/whillist.html

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