CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) collected different types of data to investigate a multistate outbreak of Salmonella Thompson infections. Epidemiologic, laboratory, and traceback data showed that onions processed at Gills Onions were contaminated with Salmonella and made people sick.

As of December 4, 2023, a total of 80 people infected with the outbreak strain of Salmonella were reported from 23 states: Arizona 1, California 17, Colorado 1, Georgia 1, Iowa 1, Idaho 1, Illinois 4, Indiana 2, Kentucky 1, Massachusetts 1, Michigan 6, Montana 2, North Dakota 2, New York 1, Ohio 3, Oregon 3, Tennessee 1, Texas 1, Utah 19, Virginia 3, Washington 4, Wisconsin 4 and Wyoming 1. Illnesses started on dates ranging from August 2, 2023, to November 11, 2023. Of the 72 people with information available, 18 (25%) were hospitalized. One death from Wisconsin was reported.

Public health investigators used the PulseNet system to identify illnesses that may have been part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS). WGS showed that bacteria from sick people’s samples were closely related genetically. This suggested that people in this outbreak got sick from the same food.

The outbreak strain was identified by FDA in October 2023 in environmental samples collected from the farm where the onions were grown. Other Salmonella strains were also identified from samples taken from the onion farm. CDC identified people who got sick with these strains of Salmonella, but there was not enough epidemiologic or traceback evidence to confirm these illnesses were part of the outbreak.

FDA conducted a traceback investigation and determined that onions processed at Gills Onions were available at points of service where people ate prior to becoming ill. Meal records from the long-term care facilities showed that people were served diced onions from Gills Onions.

On October 23, 2023, Gills Onions recalled fresh diced onion products.