The US Food and Drug Administration said on Friday that 75 people had now been infected by the E coli outbreak linked to McDonald’s quarter pounder hamburgers, as the number sickened by the bacterial illness continues to increase.
And the Centers for Disease Control and Prevention (CDC) warned on Friday: “The true number of sick people in this outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses.”
The update signaled an escalation of the food poisoning outbreak from the previous government report that the infections so far had killed one person, sickened 49 and hospitalized 10 across in the US. The outbreak has chiefly affected the US west and midwest after first emerging in Colorado.
On Thursday, fingers were pointed at fresh onions as the possible source of the deadly bacteria, not the burger meat as may have been expected.
The FDA said then that 22 people out of those about whom information was available had been hospitalized. Two of them have developed hemolytic uremic syndrome, a serious condition that can cause kidney failure.
The company has pulled the quarter pounder item from its menu at McDonald’s locations in Colorado, Kansas, Utah and Wyoming and in parts of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico and Oklahoma. These account for a fifth of its 14,000 US restaurants. Shares of the world’s largest burger chain were down 2% on Friday morning.
The CDC also said in its warning: “This is because many people recover without medical care and are not tested for E coli. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.”
Past outbreaks of the bacterial disease have hampered sales at big fast food restaurants, as customers shun the affected chains.
Yum Brands said on Thursday that it was removing fresh onions from menus “out of an abundance of caution” at some of its KFC, Pizza Hut and Taco Bell chains.
Restaurant Brands International, the parent company of Burger King, the McDonald’s rival, removed onions from its menu at at least one outlet in Colorado, the state at the center of the McDonald’s outbreak.
“We’ve been told by corporate to not use any onions going forward for the foreseeable future,” said Maria Gonzales, the on-duty manager inside a Burger King in Longmont, Colorado, on Wednesday. “They’re off our menu.”
Illnesses from the McDonald’s items started on dates ranging from 27 September to 10 October.
Reuters contributed reporting