SAN FERNANDO, Calif. (AP) — At least 10 individuals in the United States have been affected by a listeria outbreak associated with ready-to-eat food products, prompting a producer to voluntarily recall multiple items, federal officials announced.

The U.S. Food and Drug Administration reported on Saturday that federal, state, and local authorities are looking into the outbreak, which has been traced to products made by Fresh & Ready Foods LLC located in San Fernando, California. According to the FDA, the 10 individuals who became ill were from California and Nevada, and they required hospitalization.

The agency noted that these products were distributed in Arizona, California, Nevada, and Washington at various venues including retail outlets and food service locations such as hospitals, hotels, convenience stores, airports, and by airlines.

Listeria symptoms usually start within two weeks of eating contaminated food. Mild cases can include fever, muscle aches, nausea, tiredness, vomiting and diarrhea, while more severe symptoms may include headache, stiff neck, confusion, loss of balance and convulsions.

Federal officials said they started investigating the recent outbreak last year but didn’t have enough evidence to identify a source of the infections. They said the investigation was reopened in April when FDA investigators found listeria in samples collected from Fresh & Ready Foods that matched the strain from the outbreak.

The FDA found that six of the 10 people who got sick had been hospitalized before becoming ill with listeria. The FDA found that items made by Fresh & Ready Foods had been served in at least three of the health care facilities where the patients had been previously treated.

The Centers for Disease Control and Prevention said that the test samples from sick patients were collected from December 2023 to September 2024.

Fresh & Ready voluntarily recalled several products, which can be identified by “use by” dates ranging from April 22 to May 19 of this year under the brand names Fresh & Ready Foods, City Point Market Fresh Food to Go and Fresh Take Crave Away.

A message seeking comment from Fresh & Ready Foods was left Sunday.