Frozen shakes sold to nursing homes, hospitals and other institutions have been recalled after the drinks were tied to a yearslong deadly listeria outbreak, the Food and Drug Administration said on Friday.
Since 2018, at least 11 people have died from the outbreak and dozens have been hospitalized, the F.D.A. said, but previous investigations had not been able to find a source of the bacteria.
In 37 of the 38 known cases, the patients were hospitalized; 34 of those infected were in long-term care facilities or had been hospitalized before becoming sick with listeria.
Cases have been reported in 21 states, including California, Florida and New York. Since January 2024, there have been 20 cases, and the outbreak is ongoing, the F.D.A. said.
The F.D.A. said on Friday that the outbreak had been linked to Lyons ReadyCare and Sysco Imperial frozen shakes, which are made to supplement meals. They come in four-ounce cartons and in flavors such as vanilla, strawberry and chocolate.
The F.D.A. said that it had been notified about a listeria outbreak on Nov. 25 and had started an investigation that found a connection to the frozen shakes after a review of records at facilities where people who contracted the infection had been living.
The Centers for Disease Control and Prevention has been working with the F.D.A. to investigate the outbreak.
Lyons Magnus, the food service company that distributes the drinks, said on Saturday in a news release that it was recalling the shakes because they could be contaminated with the bacteria, Listeria monocytogenes.
The company said the drinks had mostly been sold to long-term care facilities and were not available for retail sale.
Most people who get sick from food contaminated by listeria show symptoms such as fever, diarrhea, vomiting and muscle aches for a few days, or no symptoms at all.
Some groups, including people who are 65 and older, who are pregnant or who have weakened immune systems, are at a higher risk of having a serious infection. Symptoms can appear on the same day a person eats contaminated food or as late as 10 weeks later, according to the F.D.A.
The drinks were manufactured by Prairie Farms Dairy at a facility in Fort Wayne, Ind., Lyons Magnus said. Prairie Farms did not immediately respond to a request for comment on Sunday.
Sysco, a food distribution company, said in a news release on Friday that it had recalled the shakes and stopped the purchase of other products supplied by Lyons Magnus from the facility in Fort Wayne.
“Sysco expresses our most sincere condolences with those affected by this outbreak and their families,” the company said in a statement.