"Throw away any unlabeled onions at home. Do not eat, sell, or serve red, white, or yellow onions imported from Mexico and distributed U.S.-wide by ProSource Inc," the US Centers for Disease Control and Prevention (CDC) warned in a tweet.
The CDC said 652 people have been infected with salmonella -- and there have been 129 hospitalizations. No deaths have been reported.
"Epidemiologic and traceback data show that one source of infections in this outbreak are whole red, white, and yellow onions imported from Chihuahua, Mexico, and distributed throughout the United States by ProSource Inc," the CDC said in a statement.
Multiple people who contracted salmonella ate onions at the same restaurant, according to epidemiological interviews conducted by the CDC.
The number of people sick with this salmonella outbreak is likely higher than reported, and it's possible the outbreak isn't limited to the reported states, the CDC said.
"This is because many people recover without medical care and are not tested for Salmonella," the agency said.
In addition to throwing away onions, people should wash surfaces where there was contact and reach out to a doctor if severe salmonella symptoms develop. Symptoms include bloody diarrhea and a high fever, extensive vomiting and signs of dehydration, which usually begin six hours to six days after infection, according to the CDC.
Federal health officials are investigating to determine whether other onions and suppliers are linked to this outbreak.
An estimated 1.35 million Salmonella cases occur annually in the US, with about 420 deaths, according to the CDC. Infection usually happens by eating foods contaminated with animal feces.
Onions last year were also the cause of a Salmonella outbreak that infected 640 people from more than 40 states.
Also last year, at least 55 people became sick in 12 different states after a salmonella outbreak was linked to dried wood ear mushrooms, the CDC said. And peaches and their products were recalled in 2020 after 101 people were sickened in 17 states by salmonella poisoning linked to the fruit.