Large Salmonella outbreak linked to onions, CDC warns

Red, white and yellow onions.
(Image credit: leventina/Getty Images)

A Salmonella outbreak tied to whole red, white and yellow onions has sickened more than 650 people in 37 states, according to the Centers for Disease Control and Prevention (CDC).

The onions were imported from Chihuahua, Mexico, and distributed by ProSource Inc., according to a statement from the agency.

The affected onions may have a sticker or packaging with the name of the distributor (ProSource Inc.) and country of origin (Mexico). The CDC urged consumers to throw away any whole red, white or yellow onions that they have at home if the onions do not have a label or packaging indicating their source.

So far, health officials have identified 652 cases tied to the outbreak. Of these people, 129 were hospitalized, and no deaths have been reported. Officials said the number of people who have been sickened in the outbreak is likely much higher, however, in part because many people who fall ill may recover without being tested for Salmonella

Related: Top 7 germs in food that make you sick

CDC officials first announced their investigation into the Salmonella outbreak on Sept. 17, but at that time, the source had not been identified. Now, officials have pinpointed onions as the source — interviews with ill people found that 75% reported eating raw onions or dishes with raw onions before they became sick, the statement said. (Interviews for foodborne illness investigations can take place weeks after a person becomes ill, and not everyone may remember all the foods they ate before they got sick, according to the CDC, which may in part explain why 25% of people did not report eating onions. In addition, people are not always aware of all the ingredients in the foods they eat.) 

What's more, multiple people who were ill reported eating at the same restaurants. It turned out that ProSource supplied onions to many of these restaurants. Investigators also identified the specific strain of Salmonella making people sick —  Salmonella Oranienburg — in a condiment cup containing leftover cilantro and lime obtained from a sick person's home. The person reported that the container had also contained onions, but no onions were left, according to the CDC.

ProSource has voluntarily recalled the affected onions. The company told health officials that the last batch of onions it received from Mexico was imported on Aug. 27, 2021. Because these onions can last up to three months, they could still be in homes and businesses, the statement said.

Symptoms of Salmonella infection include diarrhea, fever and stomach cramps, which begin six hours to six days after a person consumes food contaminated with the bacteria. Most people who get sick with Salmonella recover within four to seven days without specific treatment, the statement said. Young children, older adults and people with weakened immune systems are at higher risk of severe illness from Salmonella. Symptoms of severe illness can include a fever higher than 102 degrees Fahrenheit (38.8 degrees Celsius), bloody diarrhea, excessive vomiting and dehydration, according to the CDC.

Officials are still investigating whether additional onions or suppliers are tied to the outbreak, the statement said.

Originally published on Live Science.  

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.