CDC: Throw Out Unlabeled Onions Over Potential Salmonella Contamination

At least 652 illnesses have been reported in 37 states.

Published Oct. 21, 2021

Image Via Screengrab/CDC

The Centers for Disease Control and Prevention (CDC) is investigating onions contaminated with salmonella that were imported to the U.S. from Mexico after at least 652 people across 27 states had fallen ill, as of Oct. 21, 2021.

The last of the imported onions were sold to restaurants and grocery stores across the nation on Aug. 27, but the distributor, ProSource Inc., said that the bulbs can last up to three months in storage and may still be on kitchen shelves and counters.

Experts recommend businesses and consumers check all food storage for any potentially contaminated onions and toss those imported from Chihuahua, Mexico, and distributed by ProSource Inc. Onions purchased at grocery stores should have stickers or packaging that indicate the brand (ProSource Inc.) and the country (Mexico) where they were grown, but if an onion is unlabeled, throw it out and sanitize any surfaces that it may have come into contact with.

“If you can’t tell where the onions are from, don’t buy or eat them,” wrote the health agency.

Salmonella infection, known as salmonellosis, is caused by bacteria that affects the intestinal tract. Most cases resolve on their own without any medical intervention, but some people, especially young children and the elderly and those with compromised immune systems, may experience severe illnesses that could require hospitalization. Symptoms usually begin between six hours and six days after ingesting the bacteria and can cause diarrhea, fever, and stomach cramps.

At the time of this writing, the CDC, U.S. Food and Drug Administration (FDA), and public health and regulatory officials were working across state lines to collect data to establish a timeline and distribution path after an initial outbreak of 20 infections was first identified on Sept. 2.

“As of October 18, 2021, 652 people infected with the outbreak strain of Salmonella Oranienburg have been reported from 37 states. Illnesses started on dates ranging from May 31, 2021, to September 30, 2021,” wrote the CDC.

The CDC warns that the outbreak may not be limited to the states shown in the above map, as many people recover from Salmonella without being tested or medical care. CDC

Those reporting illnesses ranged in age from less than a year old to 97 years old. Of the more than 400 people who submitted detailed information, nearly one-third had been hospitalized. No deaths had been reported as of this writing.

“The true number of sick people in an outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak,” the CDC noted.   

An FDA analysis identified that many of those who got sick ate at restaurants. One cluster of cases occurred in an unnamed restaurant that investigators collected a condiment container from with leftover lime and cilantro in it, which tested positive for salmonella. A customer reported that the condiment cup had also contained onions, though no onions were left in the container at the time of testing. Further testing of the bacteria in samples taken from 609 people did not show any antibiotic resistance, while three showed a resistance to some of the most common antibiotics.

“Most people with Salmonella illness recover without antibiotics,” added health officials. “However, if antibiotics are needed, this resistance is unlikely to affect the choice of antibiotic used to treat most people because it is rare.”

Plot, Text, Diagram
Recent illnesses may not yet be reported as it usually up to a month to determine if a sick person is part of an outbreak. Screengrab/CDC


CDC. “CDC: Salmonella Outbreak Linkd to Onions.” Centers for Disease Control and Prevention, 20 Oct. 2021,

CDC. “Reporting Timeline for Foodborne Outbreaks.” Centers for Disease Control and Prevention, 3 June 2021,

nvestigating Outbreaks | Foodborne Outbreaks | Food Safety | CDC. 16 Nov. 2018,

Questions and Answers | Salmonella | CDC. 5 Dec. 2019,

Madison Dapcevich is a freelance contributor for Snopes.