The federal agency says whole red, white, and yellow onions imported from Chihuahua, Mexico, and distributed throughout the United States by ProSource seem to be the source of the infections. If you’re not sure where the onions originated, you should throw them away, the CDC warns.

ProSource has issued a recall on the onions.

Some 652 people have been reported sick in 37 states, according to the CDC. Of those, 129 people have been hospitalized. No deaths have been reported.

The CDC says the onions were last imported into the U.S. on Aug. 27. But onions have a long shelf life—up to three months—so they may be sitting unused in homes and businesses, including restaurants. The first salmonella case related to the onions was discovered on May 31, and reported cases escalated substantially in August.

Salmonella can spread in a variety of foods. In the past few years, health officials at the USDA have recalled items such as contaminated ground turkey, flour, and spinach to prevent transmission.

People infected with salmonella can expect symptoms that include diarrhea, abdominal cramps, and fever beginning six hours after consumption. The illness can stretch from four to seven days, but most patients recover without needing medical treatment. Children younger than 5, adults 65 and older, and people with weakened immune systems are more likely to have severe illness.

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