Consumers who have symptoms should contact their health care provider to report their symptoms and receive care. To report a complaint or adverse event (illness or serious allergic reaction), 
visit Industry and Consumer Assistance.

CDC, FDA, USDA FSIS, and public health officials in multiple states are investigating an outbreak of E. coli O157:H7 infections. Most people in this outbreak are reporting eating the Quarter Pounder hamburger at McDonald’s before becoming sick. It is not yet known which specific food ingredient is contaminated.

McDonald’s is collaborating with investigation partners to determine what food ingredient in Quarter Pounders is making people sick. McDonald’s stopped using fresh slivered onions and quarter pound beef patties in several states while the investigation is ongoing to identify the ingredient causing illness.