CDC, public health and regulatory officials in several states, the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS) are collecting various types of data to diagnose an outbreak of Investigate epidemics in multiple states E.coli O157:H7 infections.

Epidemiological and tracing data indicate that fresh, sliced ​​onions served at McDonald's were the likely cause of this outbreak.

Epidemiological data

As of October 30, 90 people had been infected with the outbreak strain E.coli O157:H7 has been reported from 13 states. The illnesses occurred between September 27, 2024 and October 16, 2024. Of 83 people with available information, 27 were hospitalized and 2 people developed hemolytic uremic syndrome, a serious condition that can lead to kidney failure. One death of an older adult has been reported in Colorado. This person is not one of those who developed HUS.

The actual number of people sickened in this outbreak is likely much higher than the reported number, and the outbreak may not be limited to those states with known illnesses. This is because many people recover without medical care and are not tested E.coli. Additionally, recent illnesses may go unreported because it typically takes three to four weeks to determine whether a sick person is part of an outbreak.

Public health officials collect many different types of information from sick people, including their age, race, ethnicity, other demographics and the foods they ate in the week before they became ill. This information provides clues to help investigators identify the source of the outbreak.

The following table provides information about sick people in this outbreak (“n” is the number of people for whom information is available for each population group).

State and local health officials are surveying people about the foods they ate in the week before they became ill. Of the 62 people surveyed, all 62 (100%) said they had eaten at McDonald's. 58 people were able to remember specific menu items they had eaten at McDonald's. 48 of 58 people (83%) said a menu item contained fresh, sliced ​​onions. 46 of 58 people (79%) reported a menu item that consisted of fresh quarter-pound beef patties. In total, three people reported menu items that included fresh, slivered onions, but no fresh quarter-pound beef patties. One person reported a menu item with a fresh quarter-pound beef patty, but no fresh, sliced ​​onions

Some people affected by this outbreak reported traveling to other states before their illness began. At least three people ate at McDonald's during their trip.

Traceability information and laboratory data

The FDA has initiated inspections at a Taylor Farms processing center in Colorado and at an interesting onion grower in Washington state. The FDA is currently unable to blame any producer.

On October 22, Taylor Farms, the supplier of sliced ​​onions to affected McDonald's locations, initiated a recall of yellow onions. Customers were contacted directly by Taylor Farms and asked to remove products. FDA is working closely with affected companies and will continue to provide updates, including any additional recalls that may be necessary for companies that have received recalled onions.

On October 22, Colorado Department of Agriculture (CDA) laboratories analyzed subsamples of all batches of fresh and frozen McDonald's brand beef patties collected from various McDonald's locations in Colorado and found them negative E.coli. All beef tests is completed.

FSIS has conducted a thorough investigation, including tracing beef patties served on Quarter Pounders at McDonald's, and there is no evidence that ground beef is the likely source of contamination. FSIS used specific meal information reported by sick individuals to trace beef patties through the supply chain to the facilities where they were produced and did not identify any source of beef. FSIS will continue to work closely with federal and state partners.

Public health measures

Since onions have been recalled, it is not necessary to avoid eating onions or other foods prepared with onions. Call your doctor if you have a serious illness E.coli Symptoms.