One Death, and Several Illnesses Reported in McDonald’s E. Coli Outbreak
The slivered onions on Quarter Pounders are the likely source.

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An urgent message to fast-food fans: The U.S. Centers for Disease Control and Prevention (CDC) announced on Tuesday, October 22, that it was investigating a multi-state E. coli outbreak linked to McDonald’s Quarter Pounders.
The rapidly developing investigation is also being conducted by the U.S. Food and Drug Administration (FDA), the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS), and public health and regulatory state officials.
“Epidemiologic data show that Quarter Pounder hamburgers served at McDonald’s are contaminated with E. coli and are making people sick,” the CDC said in an online alert.
The early indication is that slivered onions served on the Quarter Pounder burgers are the likely source of the E. coli O157:H7 outbreak, although investigation is still ongoing. It’s also possible that the culprit is the beef patties themselves, according to the CDC.
So far, 49 people across 10 states have been confirmed to have been infected with E. coli O157:H7, with the onset of illness ranging from September 27 to October 11, 2024. While the agencies have specific information about only 28 of those sickened in the outbreak, 10 of those 28 have been hospitalized. One person (a child, NPR reports) has developed a serious illness known as hemolytic uremic syndrome (HUS), which can lead to kidney failure. And one other person — not with HUS — has died as a result of the outbreak. That person is an older adult who lived in Colorado.
“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,” the CDC warns. “This is because many people recover without medical care and are not tested for E. coli.”
Another factor in a potential undercounting, thus far, of those sickened in the outbreak is that it often takes several weeks to conclude that an illness is linked to a particular outbreak.
Demographic information gathered by the health agencies indicate that those sickened range between the ages of 13 and 88 years old, with a median age of 26, and most of them (63 percent) are male. Ninety-three percent of those sickened in the outbreak are White, seven percent are Black and none are Hispanic.
All 18 of the people interviewed by health officials in connection with the outbreak report eating at McDonald’s, with 16 of those saying they ate a beef hamburger, in some cases while traveling. Fourteen people said they remembered which specific hamburger they ate at McDonalds — and 12 of those people say they ate a Quarter Pounder hamburger.
In a statement, McDonald’s says the slivered onions implicated in the outbreak were “sourced by a single supplier that serves three distribution centers.” As a precaution, the chain says, it had stopped serving slivered onions and Quarter Pounders in several states, including Colorado, Kansas, Utah and Wyoming, along with parts of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico and Oklahoma.
“We take food safety extremely seriously and it’s the right thing to do,” McDonald’s North America Chief Supply Chain Officer Cesar Piña says in an “internal message” shared online.
Health officials are also working to ascertain whether the onions were delivered to other businesses as well.
Anyone who has recently eaten a McDonald’s Quarter Pounder hamburger and developed severe E. coli symptoms is encouraged to contact their healthcare provider.
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