As of October 30, 2024, the U.S. Centers for Disease Control and Prevention (CDC) has officially named fresh, slivered onions served at McDonald’s as the source of the recent Escherichia coli O157:H7 outbreak. The onions were sourced from a Taylor Farms facility in Colorado Springs, Colorado.

CDC also reported new illnesses associated with this outbreak, for a total of 90 illnesses, 27 hospitalizations, and one death in 13 U.S. West and Midwest states. Apart from the fatality, two people have developed Hemolytic Uremic Syndrome (HUS), which has resulted in kidney failure in at least one patient—a 15-year old girl residing in Colorado.

Although CDC expects additional outbreak patients to be identified as the investigation continues, the current public health risk of being infected by the outbreak strain is low, as Taylor Farms has recalled the implicated onions and McDonald’s—as well as other restaurant chains supplied by Taylor Farms—removed fresh onions from their menus at affected locations.

Prior to the confirmation of slivered onions as the vehicle of illness in this outbreak, beef patties used at McDonald’s were ruled out as the cause of sickness.