The CDC released this Investigation Update: E. coli Outbreak, Onions Served at McDonald’s – October 30, 2024:
CDC, public health and regulatory officials in several states, the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS) are collecting different types of data to investigate a multistate outbreak of E. coli O157:H7 infections.
Epidemiologic and traceback data show that fresh, slivered onions served at McDonald’s were the likely source of this outbreak.
Epidemiologic data
As of October 30, 90 people infected with the outbreak strain of E. coli O157:H7 have been reported from 13 states. Illnesses started on dates ranging from Sept 27, 2024, to October 16, 2024. Of 83 people with information available, 27 have been hospitalized, and 2 people developed hemolytic uremic syndrome, a serious condition that can cause kidney failure. One death has been reported from an older adult in Colorado. This person is not one of those who developed HUS.
The true number of sick people in this 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 E. coli. 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.
Public health officials collect many different types of information from sick people, including their age, race, ethnicity, other demographics, and the foods they ate in the week before they got sick. This information provides clues to help investigators identify the source of the outbreak.
The table below has information about sick people in this outbreak (“n” is the number of people with information available for each demographic).
State and local public health officials are interviewing people about the foods they ate in the week before they got sick. Of the 62 people interviewed, all 62 (100%) report eating at McDonald’s. Fifty-eight people were able to remember specific menu items they ate at McDonald’s. Forty-eight of 58 people (83%) reported a menu item containing fresh, slivered onions. Forty-six of 58 people (79%) reported a menu item made with fresh quarter pound beef patties. Overall, three people reported menu items that contained fresh, slivered onions, but not fresh quarter pound beef patties. One person reported a menu item with a fresh quarter pound beef patty but without fresh, slivered onions
Some people in this outbreak reported traveling to other states before their illness started. At least three people ate at McDonald’s during their travel.
Traceback information and laboratory data
FDA has initiated inspections at a Taylor Farms processing center in Colorado and an onion grower of interest in Washington state. FDA is unable to implicate a grower at this time.
On October 22, Taylor Farms, the supplier of slivered onions for affected McDonald’s locations, initiated a recall of yellow onions. Customers were contacted directly by Taylor Farms and asked to remove products. FDA is working closely with the implicated firms and will continue to provide updates including any additional recalls that might be needed for businesses who received recalled onions.
On October 22, the Colorado Department of Agriculture (CDA) laboratories analyzed subsamples from all the lots of McDonald’s brand fresh and frozen beef patties collected from various McDonald’s locations in Colorado and found them to be negative for E. coli. All beef testing has been completed.
FSIS has conducted a thorough investigation, including traceback of beef patties served on Quarter Pounders at McDonald’s, and evidence does not point to ground beef as the likely source of contamination. FSIS used specific meal information reported by ill people to trace beef patties through the supply chain to the establishments where they were produced and did not identify a beef source. FSIS will continue to work closely with federal and state partners.
Public health actions
Because onions have been recalled, it is not necessary to avoid eating onions or other foods made with onions. Call your healthcare provider if you have severe E. coli symptoms.
