Key Takeaways McDonald's said that it will bring Quarter Pounders back to some 900 restaurants in Colorado, Kansas, and Wyoming, as well as portions of nine other states, after an E. coli outbreak last week. Company officials identified slivered onions from distributor Taylor Farms' Colorado Springs facility as the likely source, and won't be serving them on the burger when sales resume there. A number of other chains like Taco Bell and Burger King said they also have removed onions sourced from the same Ta ...