8 cases of Listeria reported across Maryland and Virginia

Listeria is a persistent germ that can easily spread amongst deli equipment, surfaces, hands and food. Symptoms usually start within 2 weeks after eating food that is contaminated with Listeria, but could start as early as the same day, or as late as 10 weeks after.

"You cannot see, taste or smell this bacteria. So you won't know for sure," said Barbara Kowalcyk. Kowalcyk is an Associate Professor and Director of Institute for Food Safety and Nutrition Security at George Washington University.

She told WUSA9, that you can reheat deli meat to an internal temperature of 165 degrees, but you should try and avoid eating meats that were sliced at any deli counter.  

"When in doubt, throw it out," she said.

"This is a serious food born pathogen. It can grow when it's in your refrigerator. A lot of bacteria that causes food born illnesses can't grow at refrigerated temperatures but listeria can. If you think you have some of this product in your refrigerator you should probably clean your refrigerator thoroughly because again you don't want it cross contaminate something in your refrigerator," said Kowalcyk.

Those most at risk, are people who are pregnant, those who are 65 years or older, and anyone with a weakened immune system.

So far cases have been reported in 12 states, including Maryland and Virginia.

All of the 28 illnesses reported resulted in hospitalizations, including a person who got sick during their pregnancy. The person remained pregnant after recovering. 

People who are pregnant usually experience only fever, fatigue and muscle aches, the CDC says, but the illness can cause pregnancy loss or premature birth, and can cause serious illness or death in newborns. 

Symptoms for people who are not pregnant include 

For more details about the outbreak, click here.