One person has died, and dozens have become ill from E. coli infections linked to McDonald’s Quarter Pounder hamburgers across ten states, with Colorado reporting the highest number of cases at 26, according to the U.S. Centers for Disease Control and Prevention (CDC) on Tuesday.
The outbreak has affected 49 people in total, with 10 hospitalized. The strain involved, E. coli O157, is known for causing severe illness and was responsible for a notable outbreak in 1993 that resulted in the deaths of four children who ate undercooked hamburgers at Jack in the Box.
Following the announcement, McDonald’s shares fell approximately 6% in after-hours trading. A livestock trader indicated that the outbreak could also put pressure on U.S. cattle futures by affecting beef demand.
All individuals interviewed as part of the investigation reported eating at McDonald’s prior to their illness, with most specifically mentioning the Quarter Pounder. While the exact ingredient linked to the outbreak has not been identified, investigators are focusing on fresh, slivered onions and fresh beef patties, according to the CDC.
Colorado and Nebraska have reported the most illnesses. Cesar Pi’a, the Chief Supply Chain Officer of McDonald’s North America, revealed that preliminary results indicate a possible connection between a subset of illnesses and slivered onions from a single distributor that supplies three distribution centers.
In response, McDonald’s has removed the slivered onions and beef patties used in Quarter Pounder hamburgers from locations in the affected states while the investigation continues.
Bill Marler, a U.S. food safety attorney who represented a victim in the Jack in the Box outbreak, cautioned that more cases may arise. He noted that onions have previously been associated with E. coli O157 outbreaks. Marler emphasized that beef contamination is less common due to food safety protocols, stating that “multiple restaurants would need to undercook the meat” for it to occur.
McDonald’s is temporarily discontinuing the Quarter Pounder at restaurants in the impacted areas, including Colorado, Kansas, Utah, and Wyoming, and is working with suppliers to replenish stock in the coming week.
- coli symptoms include severe stomach cramps, diarrhea, and vomiting; they typically appear three to four days after consuming contaminated food or drink, although symptoms can arise anywhere from one to ten days after exposure, as per Colorado’s public health department.
In 2015, Chipotle faced significant sales declines and reputational damage due to E. coli outbreaks in several states, linked to a different strain that generally causes less severe illness than E. coli O157.
In addition to Colorado, the CDC reported small clusters of illnesses in Nebraska, Utah, and Wyoming related to the Quarter Pounder, with isolated cases in Kansas, Missouri, Oregon, Iowa, Wisconsin, and Montana.
