Here’s what to do with deli meats as the CDC investigates a listeria outbreak across the U.S.

NEW YORK — As US health officials investigate a deadly outbreak of listeria food poisoningthey advise pregnant women, the elderly and people with weakened immune systems not to eat sliced ​​meats unless they have been recooked at home and are therefore piping hot.

The US Centers for Disease Control and Prevention has not issued a food recall as of Saturday morning, as it is unclear which specific products are contaminated with the bacteria that have now been blamed for two deaths and 28 hospitalizations in 12 states. This means that the contaminated food could still be in circulation and that consumers should consider their personal risk level when consuming processed meats.

Federal health officials Friday warned that the number of illnesses is likely an underestimate because people recovering at home are unlikely to be tested. For the same reason, the outbreak may have spread beyond the states where listeria infections have been reported, particularly in the Midwest and along the East Coast of the U.S.

The largest number of sick people — seven — was in New York, according to the CDC. The people who died came from Illinois and New Jersey.

Of the people researchers were able to interview, “89% reported eating meat that had been cut in a deli, most commonly turkey, liverwurst, and ham that had been cut in a deli. Meat was cut in a variety of grocery stores and delis,” the CDC said.

Samples collected from victims between May 29 and July 5 show the bacteria are closely related genetically.

“This information suggests that meat cut in the deli is a likely source of this outbreak. However, at this time, CDC does not have enough information to say which deli is the source of this outbreak,” the agency said in a statement posted on its website Friday.

Listeria infections usually cause fever, muscle aches, and fatigue, and can cause stiff neck, confusion, loss of balance, and convulsions. Symptoms can develop quickly or up to 10 weeks after eating contaminated food.

It can be diagnosed by testing body fluids, usually blood and sometimes urine or spinal fluid, according to the Mayo Clinic.

Listeria infections are especially dangerous for people over 65 and those with weakened immune systems, the CDC said. Victims in this outbreak ranged in age from 32 to 94, with a median age of 75.

For pregnant people, listeria can increase the risk of miscarriage. One of the victims in the current outbreak was pregnant but did not miscarry, officials said.

Infections limited to the intestines — intestinal listeriosis — can often be treated without antibiotics, according to the CDC. For example, people may need extra fluids if they have diarrhea.

But if the infection spreads beyond the intestines (invasive listeriosis), it is extremely dangerous and is often treated with antibiotics to reduce the risk of blood infections and brain inflammation, the Mayo Clinic says.

So far, there’s no evidence that people are getting sick from prepackaged deli meats. And for at-risk groups who already have deli meats in their refrigerators, they can be sanitized by recooking them. “Refrigerating does not kill Listeria, but reheating before eating kills any bacteria that may be on these meats,” the CDC says.

This isn’t new advice: The CDC always advises people at higher risk of listeriosis not to eat meat that’s been sliced ​​at the deli, or to heat meat to an internal temperature of 165 degrees Fahrenheit or until it’s piping hot before eating it.

Some products involved in previous listeria outbreaks obviously cannot be reheated: over the decades, listeria has prompted voluntary or mandatory recalls of cheeses, bean dips, milkmushrooms, packaged saladsAnd ice cream.

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