(Bloomberg) -- People across the U.S. have been advised to throw away all unlabeled red, white and yellow onions after a mass salmonella outbreak sickened hundreds of people across 37 states.

The Centers for Disease Control and Prevention said one source of infections had been traced to onions imported from Chihuahua, Mexico, and distributed by ProSource Inc. 

So far 652 people have been reported sick, with 129 hospitalized. No deaths have been reported. The CDC said the actual number of people made ill was likely to be much higher, with most going unreported. Infections were recorded between May 31 and Sept. 30.

“Interviews with sick people show that 75% of people ate or possibly ate raw onions or dishes likely containing raw onions before they became sick,” the CDC said in a statement. “Several ill people reported eating at the same restaurants, indicating they may be part of illness clusters.”

The CDC advises people not to buy any onions imported from Chihuahua, to throw away all onions that don’t have a sticker or packaging and to wash all surfaces and container that may have touched the onions using hot soapy water or a dishwasher. Symptoms of salmonella include diarrhea, fever and stomach cramps that start six hours to six days after eating contaminated food.

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