An E. coli outbreak linked to McDonald’s Quarter Pounder burgers has resulted in 10 hospitalizations and one death, according to the CDC. The agency reported forty-nine cases in ten states, with Colorado and Nebraska seeing the highest numbers. McDonald’s has temporarily removed Quarter Pounders from menus in several Western states after identifying slivered onions as a possible source of the contamination. The company said that other beef products remain unaffected. McDonald’s shares dropped 7% in premarket trading Wednesday.