Pregnant women should take special care ordering from deli counters and cleaning their kitchens due to an ongoing listeria outbreak, the Centers for Disease Control and Prevention (CDC) said on Wednesday. Sliced meats and cheeses contaminated with Listeria monocytogenes have sickened 16 people across six states, and 13 of them required hospitalization. The true number of cases is likely higher than the reported total, the CDC added.

Here's what we know about the outbreak so far, including how you can protect yourself and your little one during your pregnancy. 

What caused the listeria outbreak?

Federal investigators have identified deli meats — cold cuts, lunch meats, hot dogs and pâtés sold at the deli — as the likely source of this particular listeria outbreak. Reported cases have occurred in New York, Delaware, Maryland, Massachusetts, Illinois and California. 

A contaminated product possibly introduced this particular strain to delis in different states, but authorities have not identified or recalled any specific foods. Listeria can easily live for a long time in restaurant display cases and on kitchen equipment, and then spread onto food. 

Pregnant women, people over the age of 65 and those with weakened immune systems are especially susceptible to falling ill from listeria. In fact, pregnant women are 10 times more likely to get listeriosis — the illness caused by the bacteria — than the rest of the population, the American College of Obstetricians and Gynecologists (ACOG) states.

"Pregnant women have depressed immune systems and so are more susceptible to bad flu cases, COVID infections and listeriosis," says Jennifer Wu, M.D., an OB/GYN and member of the What to Expect Medical Review Board. "These outbreaks of listeria pose a special risk to pregnant women because of the adverse effects on the fetus."

Contracting listeriosis can pose serious risks for a pregnancy. Potential symptoms like vomiting and diarrhea can lead to dehydration, and the infection can cause lifelong health problems for babies as well as complications like preterm labor.

How can pregnant women keep themselves safe?

You can protect yourself and your baby-to-be from listeria by taking certain precautions recommended by the CDC and ACOG:

  • Skip deli meats and cheeses, or heat them up to steaming hot. Order your favorite sandwich as a melt, or nuke the deli meats you bought in the microwave. The heat will kill any listeria bacteria potentially lingering there. (Your food should reach an internal temperature of at least 165 degrees Fahrenheit.) 
  • Avoid other risky food. Other common listeria culprits include unpasteurized milk and cheeses, refrigerated pâté and meat spreads, refrigerated smoked seafood and unwashed raw produce. It's best to hold off on these foods until after you've delivered.
  • Clean your kitchen well. Scrub your refrigerator, food storage containers, countertops and any other surface that may have touched deli meats and cheeses. 
  • Follow food safety practices. Prepare raw meat and seafood on a separate cutting board, and keep them away from other food. Use a food thermometer when you're cooking to ensure your meal is heated through.
  • Wash your hands. Suds up for at least 20 seconds before and after touching raw food, using the bathroom, changing diapers or touching animals.
  • Watch out for symptoms. Familiarize yourself with the signs of listeriosis (listed below), and call your doctor right away if you notice any.

Should pregnant women avoid deli cheese?

Previously, the CDC recommended pregnant women avoid unpasteurized soft cheeses such as queso fresco, queso blanco, panela, brie, Camembert, blue and feta. But as of this outbreak, the CDC is also advising pregnant women to avoid or heat up deli cheeses, which may include some varieties previously viewed as safe to eat.

For example, hard cheeses — such as cheddar, Swiss and provolone — from the deli counter should be served hot to reduce the risk of contracting listeriosis. Packaged, pasteurized cheeses from the dairy aisle are okay to eat as-is.

"Because the packaged cheeses still seem fine, the caution against cheeses in the delis may involve concerns about cross contamination from the infected meats in the delis," Dr. Wu says.

When to talk to your doctor

Listeriosis symptoms can appear as late as two months after eating a contaminated food. While it's still unlikely that you'll get sick, it's good to idea to know the following signs: 

  • Mild, flu-like symptoms such as fever, chills, muscle aches, fatigue, diarrhea or upset stomach
  • Stiff neck
  • Headaches
  • Confusion
  • Loss of balance

If you suspect you may have listeriosis, call your doctor ASAP. Your health care provider can do a simple blood test to check for the infection, and prescribe antibiotics if needed to treat you and protect your baby. 

While listeriosis can sound scary, remember that you can keep yourself and your baby safe by taking a few extra steps. Just order any deli sandwiches heated up, or find another lunch that satisfies whatever you're craving.