Last week, the Centers for Disease Control and Prevention (CDC) warned consumers about a listeria outbreak that had sickened 16 people in six states. Federal investigators linked the outbreak to deli cheeses and meats — which can include cold cuts, lunch meats, hot dogs and pâtés sold at the deli — that were contaminated with Listeria monocytogenes bacteria.[1]

Listeria can thrive in restaurant display cases and on kitchen equipment such as in delis, then spread onto food. If someone consumes a product that has been contaminated with listeria, they can develop listeriosis, an illness that can cause problems in pregnancy.[2]

While your odds of being infected with listeriosis are still very low, pregnant women are 10 times more likely to get listeriosis, according to the American College of Obstetricians and Gynecologists (ACOG),[3] and the illness can have serious complications. As a result, leading experts recommend moms-to-be avoid certain foods and beverages that are more likely to harbor bacteria, including deli meats, unpasteurized dairy, smoked seafood and alfalfa sprouts.

Below, What to Expect spoke to Amanda Conrad, M.P.H., an epidemiologist in the CDC’s Outbreak Response and Prevention Branch, for more on why deli meats and cheeses can be risky, how pregnant women can protect themselves and their babies, and what to do if you think you consumed a contaminated product.

The most important takeaway for moms-to-be? While the current outbreak can feel scary, listeriosis is still rare. But there are clear steps you can take to stay safe, including by heating up deli meats and cheeses until very hot or saving them until after your baby is born.

Why does the CDC recommend that pregnant women avoid deli meats?

"There are a couple of reasons why the purchase of deli meats can be high risk," says Conrad. "That's because the [listeria] germ itself is pretty hardy, and it's going to be difficult to remove from the deli environment. If it gets in the environment either on a deli cheese or deli meat, it can spread easily on the countertop, the slicer, the knife, cutting boards and on surfaces when they're cutting it. So it's really important when we're thinking about these types of products to know that the risk might not be the meat itself, but the environment that it was being processed in.

And so in general, we want to emphasize that for pregnant women listeria can cause pregnancy loss or premature birth, and it can also cause a serious type of illness or death of newborns. That's why we have these recommendations around deli meats and cheeses, especially in this particular outbreak, to heat your deli meats and cheese if you do choose to eat them, just to make sure that you're going to stay safe for baby and yourself." 

What about sliced deli cheeses that are hard varieties (such as cheddar)?

"Our general advice is to avoid soft cheeses (such as queso fresco, queso blanco, panela, brie, Camembert, blue-veined or feta) unless they're made with pasteurized milk. But for deli cheeses specifically, I think it's just safer to protect the baby and heat up the product, regardless of whether there's an outbreak going on or not. It's always the safest option to heat [deli meats and cheeses] if you choose to eat them."

How should pregnant women safely prepare deli meats or cheeses?

"For deli meats and cheeses, the risk is that they're held and processed [in a deli environment]. It's also because they are kept at a refrigerator temperature, and typically you can see that listeria likes the cold and can survive in that temperature. So heat actually does kill the listeria on these products.

If you know the temperature that you're heating it, it should be 165 degrees Fahrenheit. But as long as it's steaming hot — if you can see it physically steaming — you'll know it's been heated up. That will be what to look for."

What other steps can moms-to-be take to protect themselves from listeria?

"Our website has a list of foods that we have general recommendations for all times, not just in outbreak situations. Those are recommendations to tell you about specific items like soft cheeses, raw sprouts, undercooked eggs, things like that, and the recommendations tell you the safest way to eat them or the safest way to consume them and store them. We also have a link on our website on how to clean your refrigerator if you think you had a food in there that was possibly contaminated. And avoid cross-contamination when cooking with raw meats, clean in between using raw meats and ready-to-eat foods, that's a good idea in general, not just for listeria.

Also, pay attention to the food safety recalls and outbreak notices when you're pregnant. That's super important. We try to get those messages out as broadly as possible on our website and social media, so look there for any new food items that might pop up."

What should pregnant women do if they think they've been exposed to listeria?

"If you're worried that you might have been exposed to a recalled or contaminated product, look out for symptoms, which can be something like fever, fatigue or muscle aches. If anything seems a little bit different about your pregnancy or how you're feeling, I would take it as an opportunity to call your health care provider and let them know that you might have consumed a product that could have had listeria as soon as possible."