The E. coli O157:H7 outbreak associated with slivered onions on McDonald's Quarter Pounder hamburgers has concluded. The Centers for Disease Control and Prevention (CDC) confirmed a total of 104 cases across 14 states, with 38 of these cases requiring hospitalization and one resulting in death. Additionally, four individuals developed hemolytic uremic syndrome (HUS), a condition that can lead to kidney failure.
It is estimated that the actual number of affected individuals might be higher, as not all cases are diagnosed or reported. The CDC highlights that for every confirmed case, there could be 26 more that remain unidentified. The patients reported symptoms from mid-September to October 21, with the majority having consumed McDonald's products before falling ill. Specifically, 63 out of 75 patients recalled consuming items with fresh, slivered onions.
The source of the outbreak was identified as yellow onions from Taylor Farms, prompting a recall on October 22. McDonald's had already ceased using slivered onions and temporarily stopped offering Quarter Pounders at some locations. Investigations by the Food and Drug Administration, along with the Colorado Department of Agriculture and Colorado Department of Public Health and Environment, found one sample of the recalled onions and one environmental sample from a grower to be positive for E. coli, though not the O157:H7 strain linked to the outbreak.
Despite these findings, epidemiologic and traceback evidence indicated that the recalled yellow onions were the likely source of the outbreak.
Source: Food Safety News