Taco Bell, KFC, Pizza Hut, Burger King pull onions amid McDonald’s outbreak

Big-name fast food chains, including Taco Bell, KFC, Pizza Hut, and Burger King, are reportedly pulling onions off their menus in certain locations amid a deadly, multistate outbreak of E. coli O157:H7 linked to McDonald's Quarter Pounders.

Though the source of the outbreak bacteria has not been confirmed by the Centers for Disease Control and Prevention, the leading suspects are the beef patties and the sliced onions used on the popular burger.

On Wednesday, McDonald's onion supplier Taylor Farms recalled peeled and diced yellow onion products, according to a notice from US Foods, a supplier of food service operations.

"It is urgent that you stop using affected product as soon as possible," the notice reads. Restaurants were advised that if they had any of the recalled onions in their inventory, they should "DESTROY THE PRODUCT."

In a statement to Bloomberg, Taylor Farms said it had not detected E. coli in its onions but decided to issue the recall anyway.

"Taylor Farms Colorado removed yellow onions from the market produced out of our Colorado facility. We continue to work closely with FDA and CDC during this ongoing investigation," the company said in its statement.

On Thursday, Yum Brands—owner of KFC, Pizza Hut, and Taco Bell—followed that lead, saying it, too, would remove fresh onions from its chains' menus at some locations, according to Reuters. Restaurant Brands International, owner of Burger King, also did the same.

"We've been told by corporate to not use any onions going forward for the foreseeable future," Maria Gonzales, the on-duty manager inside a Burger King in Longmont, Colorado, told Reuters on Wednesday. "They're off our menu."

As of Thursday, the case count in the E. coli outbreak remained at 49 people in 10 states. Of those, 10 were hospitalized, including a child with a life-threatening complication. One older person in Colorado has died.

The states with cases include: Colorado (26 cases), Nebraska (9), Utah (4), Wyoming (4), and one case each in Iowa, Kansas, Missouri, Montana, Oregon, and Wisconsin.

McDonald's removed Quarter Pounders and slivered onions from restaurant menus in Colorado, Kansas, Utah, Wyoming, and portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico, and Oklahoma. In a statement, McDonald's said that for these restaurants, its onions are "sourced by a single supplier that serves three distribution centers. The fast-food giant continues to serve other beef burgers and diced onions at impacted locations.