While the E. coli outbreak has been associated with McDonald’s Quarterpounders, the investigators are working to determine the exact source.
The exact ingredient hasn’t been confirmed yet, but the people who became sick indicated that they had consumed a McDonald’s Quarter Pounder burger. They’re trying to determine if the beef patties or the onions are the contamination source.
In the states associated with the illness, McDonald’s has temporarily stopped using beef patties and slivered onions associated with Quarter Pounders. Of note, the other types of beef patties and onions used at McDonald’s haven’t been linked with this outbreak.
According to the Food & Drug Administration, McDonald’s locations in the following states have temporarily stopped using Quarter Pounder slivered onions and beef patties.
- Colorado
- Portions of Idaho
- Iowa
- Kansas
- Missouri
- Montana
- Nebraska
- Nevada
- New Mexico
- Oklahoma
- Utah
- Wyoming
As of today, “Preliminary traceback and distribution information reviewed by FDA shows that slivered onions served on Quarter Pounders are a likely source of contamination.” NPR reports that Colorado has 27 cases and Nebraska has nine.