Outbreak Investigation

Product

Slivered onions previously served on McDonald’s Quarter Pounder burgers are the likely source of contamination, based on epidemiologic and traceback data. McDonald’s is no longer using slivered onions on Quarter Pounders at stores in affected states. Diced onions used at McDonald’s have not been implicated in this outbreak. On October 22, 2024, Taylor Farms initiated a voluntary recall of some onions sent to food service customers. Food service customers who were impacted have been contacted directly.

Symptoms begin anywhere from a few days after consuming contaminated food or up to nine days later. Symptoms include severe stomach cramps, diarrhea, fever, nausea, and/or vomiting. Some infections can cause severe bloody diarrhea and lead to life-threatening conditions, such as a type of kidney failure called hemolytic uremic syndrome (HUS), or the development of high blood pressure, chronic kidney disease, and neurologic problems.

Stores Affected

McDonald’s stores in CO, KS, and WY, and portions of IA, ID, MO, MT, NE, NM, NV, OK, and UT have temporarily stopped using slivered onions.

Recalled onions were distributed to food service customers in CO, IA, ID, KS, MO, MT, NE, NM, NV, OK, UT, and WY.

At this time, FDA is not aware of any cases or affected product outside of the United States.

Status

Ongoing; updates will be provided as they become available.

Recommendation

Consumers who have already eaten slivered onions at McDonald’s and have symptoms of E. coli infection should contact their health care provider to report their symptoms and receive care immediately.
McDonald’s stores in affected states have temporarily stopped using slivered onions. Diced onions used at McDonald’s have not been implicated in this outbreak.
According to available information, it is unlikely that recalled yellow onions were sold to grocery stores or directly to consumers.
Food service customers should not sell or serve Taylor Farms recalled yellow onions and should follow FDA’s safe handling and cleaning advice and use extra care in cleaning and sanitizing any surfaces and containers that may have come in contact with recalled product to reduce the risk of cross-contamination. Customers should also ensure that they did not freeze recalled onions or foods containing recalled onions.

Current Update

October 30, 2024

FDA continues working with CDC, USDA FSIS, state partners, and involved firms to investigate an outbreak of E. coli O157:H7 infections linked to onions. Epidemiologic and traceback data show that slivered onions served at affected McDonald’s locations are the likely source of this outbreak.

As of October 30, 90 people from 13 states have been infected with the outbreak strain of E. coli O157:H7. 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 HUS, 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. More illnesses have been reported but they are from before McDonald’s and Taylor Farms took action to remove slivered onions from food service locations.

Of the 62 people interviewed, all 62 (100%) report eating 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.

FSIS has conducted a thorough investigation in response to this outbreak, 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 establishment where they were produced and did not identify a beef source. Testing on beef patties by the Colorado Department of Agriculture is complete and all samples were found to be negative for E. coli. FSIS will continue to work closely with federal and state partners.

On October 22, 2024, Taylor Farms recalled yellow onions that were supplied to McDonald’s and other food service customers. FDA is working with Taylor Farms and their direct customers to determine if additional downstream customer recalls are necessary. According to available information, it is unlikely that recalled yellow onions were sold to grocery stores or directly to consumers. Food service customers who received recalled onions were contacted and should no longer be using or serving recalled onions. These customers should also ensure that they did not freeze recalled onions or foods containing recalled onions.

In addition, FDA has initiated inspections at a Taylor Farms processing center in Colorado and an onion grower of interest in Washington state. FDA’s investigation is ongoing.

McDonald’s continues to not use slivered onions in impacted states. The current risk of illness from E. coli contamination is low because onions have been recalled and should no longer be available.

Case Count Map Provided by CDC

Map of U.S. Distribution of Recalled Taylor Farms Yellow Onions

Distribution has been confirmed for states shown below, but product could have been distributed further, reaching additional states.

Case Count

Total Illnesses: 90
Hospitalizations: 27
Deaths: 1
Last Illness Onset: October 16, 2024
States with Cases: CO, IA, KS, MI, MO, MT, NE, NM, OR, UT, WA, WI, and WY
Recalled Onion Distribution*: CO, IA, ID, KS, MO, MT, NE, NM, NV, OK, UT, and WY

*Distribution has been confirmed for states listed, but product could have been distributed further, reaching additional states.

Previous Update

October 25, 2024

The FDA, USDA FSIS, CDC, and state partners continue to work quickly and collaboratively to investigate and identify the source of illnesses linked to E. coli contamination in McDonald’s Quarter Pounders.

As of October 24, 75 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 10, 2024. Of 61 people with information available, 22 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. Of the 42 people interviewed, all 42 (100%) report eating at McDonald’s, and 39 people report eating a beef hamburger.

FDA is using all available tools to confirm if onions are the source of this outbreak. This includes working with federal and state partners and the companies involved to collect and evaluate records and distribution information as part of our traceback investigation. FDA and state partners are also collecting onion samples for analysis.

While the investigation is ongoing, Taylor Farms, the supplier of slivered onions for the affected McDonald’s locations, has initiated a voluntary recall. Recalled yellow onions were sold to additional food service customers. Customers who received recalled onions have been directly notified of the recall.

FDA is working closely with the implicated firms and will continue to provide updates as they become available, including any additional recalls or notifications that might be needed for recipients of recalled onions.

At this time, FDA is not aware of any cases or affected product outside of the United States.

October 22, 2024

The FDA, U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS), and Centers for Disease Control and Prevention (CDC), in collaboration with state and local partners, are investigating illnesses in a multistate outbreak of E. coli O157:H7 infections. A specific ingredient has not yet been confirmed as the source of the outbreak, but most sick people report eating McDonald’s Quarter Pounder burger varieties.

Investigators are working to determine if the slivered onions or beef patties on Quarter Pounder burgers are the likely source of this outbreak.

Preliminary traceback and distribution information reviewed by FDA shows that slivered onions served on Quarter Pounders are a likely source of contamination. FDA is working quickly to confirm that these onions are a source of this outbreak and to determine if these onions were served or sold at other businesses. McDonald’s has temporarily stopped using this type of onion in these states. Diced onions used at McDonald’s are not implicated in this outbreak.

FSIS is conducting traceback on hamburger patties served at McDonald’s in affected states to determine if ground beef is a source of illness. McDonald’s has also temporarily stopped selling Quarter Pounder beef patties in affected states, while the investigation is ongoing to determine the source of the outbreak.