Listeria outbreak linked to deli meats causes 2 deaths. Here's what to know about symptoms.

A listeria outbreak linked to sliced deli meats has killed two people and sickened 28 others across 12 states, according to the Centers for Disease Control and Prevention.

It is currently unknown what brands of deli meat are tied to the outbreak, but an active investigation aims to determine the specific products that may be contaminated, the agency said in an update Friday.

"Products sold at the deli, especially those sliced or prepared at the deli, can be contaminated with Listeria," the CDC notes on its website. "Listeria spreads easily among deli equipment, surfaces, hands and food."