The investigation began when epidemiologic and traceback data indicated that slivered onions were the likely source of the outbreak.
The U.S. Food and Drug Administration (FDA), in collaboration with the Centers for Disease Control and Prevention (CDC), the USDA Food Safety and Inspection Service (FSIS), and various state health departments, is actively investigating an outbreak of E. coli O157:H7 infections connected to slivered onions served at select McDonald’s locations. As of October 30, the outbreak has resulted in 90 confirmed cases across 13 states.
The investigation began when epidemiologic and traceback data indicated that slivered onions were the likely source of the outbreak. The first reported illnesses occurred between September 27 and October 16, 2024. Among the 83 individuals with detailed information, 27 have been hospitalized, and two have developed hemolytic uremic syndrome (HUS), a serious condition that can lead to kidney failure. Tragically, one death has been reported involving an older adult in Colorado, who was not among those with HUS.
Of the 62 individuals interviewed, all reported dining at McDonald’s, with 83% indicating they consumed menu items containing fresh, slivered onions. While many also enjoyed the restaurant’s famous Quarter Pounders, evidence collected during the investigation points away from ground beef as the source of contamination. FSIS traced the beef patties served on Quarter Pounders through the supply chain and found no signs of E. coli contamination in testing conducted by the Colorado Department of Agriculture.
In response to the outbreak, Taylor Farms, the supplier of the affected yellow onions, voluntarily recalled the onions distributed to McDonald’s and other food service clients on October 22, 2024. The FDA is currently coordinating with Taylor Farms to assess the need for additional recalls and to confirm that no recalled onions were sold directly to grocery stores or consumers. Food service establishments that received the recalled onions have been notified and are advised to cease their use immediately.
To bolster the investigation, the FDA has initiated inspections at a Taylor Farms processing center in Colorado and an onion grower of interest in Washington state. Meanwhile, McDonald’s has suspended the use of slivered onions in affected states, significantly reducing the current risk of E. coli contamination.
Case Overview:
- Total Illnesses: 90 confirmed cases
- Hospitalizations: 27
- Deaths: 1 reported
- States with Cases: Colorado, Iowa, Kansas, Michigan, Missouri, Montana, Nebraska, New Mexico, Oregon, Utah, Washington, Wisconsin, Wyoming
- Recalled Onion Distribution: Confirmed in states including Colorado, Iowa, Kansas, Missouri, Montana, and others
The FDA continues to gather information, conduct traceback investigations, and sample onions for analysis to confirm the source of the outbreak. As they work diligently to resolve this public health concern, consumers are urged to stay informed and follow safety guidance regarding food preparation and consumption.
For ongoing updates, the CDC has provided resources on food safety and information about E. coli. The investigation remains active, and authorities will release further details as they become available.
