Why are pregnant women at greater risk of foodborne illness?
When a woman becomes pregnant, she undergoes all sorts of physical changes that are necessary for her body to accept and nurture the growing baby in her womb.
One of those changes involves part of the mother’s immune system called “cell-mediated immunity.” When it’s working normally, cell-mediated immunity helps fight the kinds of pathogens that move from cell to cell. This doesn’t affect the part of the immune system that involves antibodies, which remains fully functioning during pregnancy.
Cell-mediated immunity is the type of immunity involved when a person has an organ transplant and the body rejects the new organ, thinking it’s a foreign invader. When a woman becomes pregnant, the body suppresses this function to allow the body to accept the fetus.
That’s all well and good, but it does put the mother and fetus at higher risk for some types of foodborne illness.
According to foodsafety.gov, the federal government’s hub for food safety information, the top five pathogens related to food poisoning during pregnancy are bacteria Listeria monocytogenes, Campylobacter, E. coli and Salmonella, and a parasite, Toxoplasma gondii. Depending on the pathogen and the severity of the illness, these can cause miscarriage, premature birth, stillbirth or birth defects in the fetus, as well as serious health problems for the mother.
Food Safety for Pregnant Women, online at foodsafety.gov/risk/pregnant, provides details about each of these pathogens as well as other guidelines, including:
- Avoid unpasteurized milk and products made from it. Soft cheeses, such as brie, feta, Camembert, Roquefort, queso blanco and queso fresco are frequently made with unpasteurized milk. Some hard cheeses are also made with raw or unpasteurized milk. Always read the label.
- Avoid unpasteurized juice or cider. Even fresh-squeezed juice has been associated with E. coli.
- Avoid raw seafood and be selective with smoked seafood. Both pose a risk from Listeria. Smoked seafood is OK only if it is canned or otherwise processed to be shelf-stable (the kind that doesn’t need refrigeration), or is an ingredient in a casserole or other dish cooked to at least 165 degrees F.
- Avoid premade ham, chicken, tuna or other meat or seafood salads, such as those you can buy in a deli. Make them at home instead.
- Don’t eat hot dogs or lunchmeats unless you’ve heated them to steaming hot — 165 degrees F.
- Be sure any eggs you eat are cooked until the yolk is firm. Any casseroles or foods containing raw eggs should be cooked to 160 degrees F. Avoid foods containing raw or undercooked eggs, including unpasteurized eggnog, cookie or cake batter, Caesar salad dressing, tiramisu, eggs Benedict, homemade ice cream and freshly made hollandaise sauce.
For more details, see foodsafety.gov/risk/pregnant.
Chow Line is a service of the College of Food, Agricultural, and Environmental Sciences and its outreach and research arms, Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH 43210-1043, or firstname.lastname@example.org.
Editor: This column was reviewed by Sanja Ilic, food safety specialist with Ohio State University Extension.
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