6 Risky Foods to Avoid While Pregnant

For a fertilized egg to implant into the uterus, the body releases hormones and experiences changes to the immune system, says Brenna Hughes, MD, professor of obstetrics and gynecology and a specialist in reproductive infectious disease at Duke University School of Medicine in Durham, N.C. That allows the embryo to implant safely but also reduces the immune system’s ability to fight off certain infections, including listeriosis.

Another reason listeria is so dangerous to a pregnant person: "The bacteria can cross the fetal-placental barrier, which protects the unborn baby,” says Sana Mujahid, PhD, manager of food safety research and testing at Consumer Reports. Other more common types of bacteria that lead to foodborne illnesses, such as salmonella and E. coli, while posing risks, don’t typically cross the barrier, Mujahid says. 

Babies can also become infected during delivery while passing through the birth canal, according to the American College of Obstetricians and Gynecologists (ACOG).

What’s more, detecting the infection in someone who is pregnant can be tricky, says Mitzi Baum, CEO of Stop Foodborne Illness, a nonprofit that advocates for improved federal food safety policies. That’s because mild symptoms such as fever, muscle aches, nausea, vomiting, and diarrhea “are similar to those of morning sickness,” she says. So a pregnant person may not immediately realize they have developed listeriosis. 

If you have those symptoms, along with a temperature of 100.6° F or higher, ask your doctor for a blood test, ACOG recommends. Getting a proper diagnosis is key because treatment typically involves intravenous antibiotics. One caution: Don’t self-treat with oral antibiotics you may have in your medicine cabinet, because they are unlikely to help and could delay effective care. 

The list of foods prone to listeria contamination is long, mainly because listeria is a hardy bacteria and spreads easily. “The bacteria thrive in the cold, damp environment of food processing plants, and can live almost indefinitely on all sorts of surfaces—stainless steel, glass, wood, porcelain, iron, plastic, polyester, propylene, rubber, waxed cardboard, and paper,” says CR’s Mujahid.  

Once it contaminates machinery in a food processing plant or winds up on equipment such as meat and cheese slicers in grocery stores and delis, it is very difficult to eliminate, Mujahid says. 

Though avoiding such a wide variety of foods may sound daunting, Mujahid recommends focusing on the foods known to pose the highest risk:

They pose a risk because the equipment—such as slicers, knives, and cutting boards—used to prepare and package these foods after they’ve been cooked can harbor listeria, says Wise from the CDC. In fact, a December 2022 study in the International Journal of Food Microbiology found that deli meats were the leading cause of listeriosis infections in the U.S. for the past five years. 

The best bet is to skip these altogether during pregnancy, Wise says. If you do consume them, heat them to 165° F, says Mujahid. 

These are the second most commonly contaminated food, according to the International Journal of Microbiology study. Listeria can get into irrigation water on a farm where the greens are grown, or farm or wild animals can contaminate the plants as well, Mujahid says.

But because leafy greens are packed with vitamins and nutrients, you don’t want to avoid them altogether. Instead, during pregnancy consider consuming greens like spinach, kale, and collard greens that can be cooked. 

“The riskiest soft cheeses are made with unpasteurized, raw milk, so check the label, Wise says. Some common examples are Brie, Camembert, queso fresco, queso blanco, queso blando, queso ranchero, and cuajada en terrón. The problem is that soft cheeses have a high water content and low acidity, Wise says, in which listeria can thrive. Even some pasteurized soft cheeses have proved risky: A recent listeria outbreak in pasturized queso fresco, cotija, and Oaxaca sickened 26 people, 23 of which were hospitalized and two deaths.  

Either skip these while pregnant or find meat spreads and pâté that do not need refrigeration before opening, such as products in cans, jars, or sealed pouches. According to the CDC, these are heat-treated to kill germs and then sealed in airtight containers. However, do refrigerate these foods after opening. 

That includes sushi, sashimi, raw shellfish, ceviche, and fish marked as nova-style, lox, kippered, smoked, or jerky. That’s because raw and smoked seafood aren’t heated enough to kill listeria, Wise says.

These are susceptible to listeria because “the conditions that you need to get a bean to sprout, which is a moist, warm environment, are also the conditions that all kinds of bacteria, including listeria, like to grow in,” Wise says. 

If you decide to eat them, heat the sprouts to the point they’re steaming in order to kill any listeria. 

All the rules of food safety—for example, using separate cutting boards for meat and vegetables, keeping the refrigerator at 40° F or below and the freezer at 0° F, regularly cleaning and disinfecting kitchen counters and other hard surfaces, preferably using a mixture of 1 tablespoon of liquid chlorine bleach with a gallon of water, and not leaving foods out longer than 2 hours (or 1 hour outside if it’s over 90° F)—are especially important if you are pregnant. In addition, there are a few extra steps you should take to reduce the risk of exposure to listeria. 

Cook all foods to 165° F. That’s the temperature needed to kill listeria. So while it’s okay for people who aren’t pregnant to cook some foods, such as fish or whole cuts of beef or pork, to just 145° F, if you’re pregnant, take extra care and cook everything to 165° F. In addition to killing listeria, “fully cooking most foods to 165° F is also a helpful way to avoid risk of foodborne illnesses in general,” says Hughes from Duke. Pro tip: Get a food thermometer to remove any guesswork while cooking, Mujahid says.

Avoid microwaving food. That includes for both cooking food and reheating it. That’s because a microwave can heat food unevenly, so there may be some pockets of underheated foods and lingering bacteria in microwaved foods, Mujahid says.

Pro tip for everyone: Be aware of food recalls by signing up for CR’s Food Safety Alert service. You’ll get a text whenever we learn of a major food recall. You can also sign up for food recall alerts directly from the FDA and the USDA.

And if your local supermarket has an email list to sign up for safety alerts and recalls, join that as well—they might communicate about recalls faster than the federal government.