At least 49 people across ten states have been sickened, and one person in Colorado has died, in an E. Coli O157:H7 outbreak linked to McDonald’s Quarter Pounder hamburgers, according to a public health alert issued by the Centers for Disease Control and Prevention (CDC) on Tuesday.
The CDC investigation, conducted in collaboration with state and local health officials, the Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS), has identified Quarter Pounder hamburgers as a likely source of the outbreak. Ten people have been hospitalized, and one child is receiving treatment for hemolytic uremic syndrome (HUS), a potentially life-threatening condition that can cause kidney failure, the CDC stated.
Most of the reported illnesses are concentrated in Colorado, with 26 cases, and Nebraska, with 9 cases. Illnesses began appearing between September 12, 2024, and October 21, 2024, the CDC reported. Individuals interviewed as part of the investigation reported consuming food at McDonald’s prior to becoming ill, with the majority specifically mentioning Quarter Pounder hamburgers.
McDonald’s has proactively removed both fresh slivered onions and beef patties used in Quarter Pounder hamburgers from stores in the affected states whereas the investigation continues, potentially leading to temporary unavailability of the burger in some locations. According to a statement released by McDonald’s, the company is working with the FDA to determine the precise source of the contamination.
The FDA is currently conducting a traceback investigation to identify the source of the contaminated ingredients. Agency officials are collecting and evaluating records and distribution information, as well as analyzing samples of onions, according to an FDA spokesperson.
Symptoms of E. Coli O157:H7 infection typically include severe stomach cramps, diarrhea (often bloody), and vomiting, usually starting three to four days after consuming the contaminated food. While most individuals recover within five to seven days, some may develop HUS, requiring hospitalization. The CDC advises anyone experiencing these symptoms after eating a Quarter Pounder at McDonald’s to seek medical care and inform their healthcare provider about their recent food consumption.
This outbreak marks the first time onions have been implicated as a potential carrier of this particular strain of E. Coli, according to McDonald’s representatives. The company stated that the onions used in Quarter Pounders in the affected areas were sourced from suppliers who routinely test for E. Coli.
As of Wednesday, October 30, 2024, McDonald’s and its onion supplier, Taylor Farms, had already taken action to remove potentially contaminated onions from food service locations, according to a public health statement released by McDonald’s. Yet, the CDC noted that additional illnesses reported after this date likely stem from exposure before the product removal.
