What to know about E. coli and the McDonald’s outbreak The Associated PressWhat we know about the McDonald’s E. coli outbreak investigation CNNCDC links McDonald’s quarter pounders to E. coli outbreak Fox NewsWhere is the Quarter Pounder being removed? McDonald’s locations in 12 states impacted amid E. coli outbreak USA TODAYMcDonald’s, Food Safety Officials Scrutinize Onions in E. Coli Outbreak The Wall Street Journal