PROVIDENCE, R.I. (WPRI) — A multi-state outbreak of listeria monocytogenes that’s caused at least one death has been linked to meats and cheeses sold at delis.

At least 16 illnesses have been reported so far, including two in Massachusetts, according to the U.S. Centers for Disease Control and Prevention (CDC). Thirteen people have been hospitalized in six states and one death was reported in Maryland.

The CDC said it’s working to identify specific products or delis that may be contaminated.

“It is difficult for investigators to identify a single food as the source of outbreaks linked to deli meats and cheeses,” the CDC said. “This is because Listeria spreads easily between food and the deli environment and can persist for a long time in deli display cases and on equipment.”

Those who are pregnant, over 65, or have weakened immune systems are at higher risk for severe disease. The CDC recommends anyone in these groups not to eat meat or cheese from a deli counter unless it is reheated to an internal temperature of 165°F or until steaming hot.