What we know about the McDonald’s E. coli outbreak investigation

An E. coli outbreak linked to McDonald’s Quarter Pounders has led to at least 49 illnesses across 10 states, including one death.

An E. coli outbreak linked to McDonald’s Quarter Pounders has led to at least 49 illnesses across 10 states, including one death. Here’s what we know. The US Centers for Disease Control and Prevention issued a food safety alert Tuesday warning that dozens of people reported eating the Quarter Pounder sandwich at McDonald’s before becoming sick. A specific ingredient has not been confirmed as the source of the outbreak, but the US Food and Drug Administration says that the slivered onions or beef patties on Quarter Pounder sandwiches are the likely source of contamination. McDonald’s has taken Quarter Pounders off the menu in about a fifth of its stores. The company has stopped using the onions as well as quarter-pound beef patties in several states – Colorado, Kansas, Utah and Wyoming, as well as portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico and Oklahoma – while the investigation continues, the CDC said. According to the agency, the beef patties are used only for the Quarter Pounders, and the slivered onions are used primarily for the Quarter Pounder and not other items. Diced onions and other types of beef patties used at McDonald’s have not been implicated in this outbreak, the FDA said.