An E. coli outbreak linked to McDonald’s Quarter Pounders has caused at least forty-nine illnesses across ten states, including one death. The US Centers for Disease Control and Prevention issued a food safety alert, with investigations ongoing. Slivered onions or beef patties used in Quarter Pounders are the suspected sources, though no specific ingredient has been confirmed. McDonald’s has temporarily removed the sandwich from some locations and halted using onions and quarter-pound beef patties in multiple states. McDonald’s stated that the affected ingredients are likely out of the supply chain, but the CDC expects more cases as the investigation continues.