In September 2021 CDC, FDA, and public health and regulatory officials in several states initiated an investigation of a multistate outbreak of Salmonella Oranienburg infections linked to onions.

Epidemiologic and traceback data show that this outbreak of Salmonella Oranienburg infections was linked to onions.

A total of 1,040 people infected with the outbreak strain of Salmonella Oranienburg were reported by 39 states, the District of Columbia, and Puerto Rico. Illnesses started on dates ranging from May 31, 2021 to January 1, 2022. Two hundred sixty people were hospitalized. There were no deaths.

Whole genome sequencing of bacteria from 788 people’s samples did not predict any antibiotic resistance. Five people’s samples were predicted to be resistant to one or more of the following antibiotics: amoxicillin-clavulanic acid, ampicillin, cefoxitin, and ceftriaxone, gentamicin, streptomycin, sulfamethoxazole, and tetracycline. Standard antibiotic susceptibility testing of three people’s samples by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also found no resistance.

In interviews, ill people answered questions about the foods they ate and other exposures in the week before they became ill. Of 193 people with information, 145 (75%) reported eating or maybe eating raw onions or dishes likely containing raw onion before they became sick. Traceback showed that illnesses in this outbreak were were linked to whole red, white, and yellow onions distributed by ProSource Produce LLC and Keeler Family Farms that were imported from the State of Chihuahua, Mexico.

The outbreak was declared over on February 2, 2022.