Following an E. coli outbreak tied to onions at McDonald's, major US chains like Burger King, Taco Bell, Pizza Hut, and KFC have removed onions from some locations. Yum! Brands, which owns these chains, announced it was pulling fresh onions "out of caution" but didn’t disclose specific locations affected. The outbreak was traced to Taylor Farms, a supplier in Colorado, which recalled certain yellow onion batches, though E. coli was not detected. The CDC linked the outbreak to pre-sliced onions on McDonald's Quarter Pounders, leading McDonald's to remove these onions from around 20% of its US locations.