McDonald's Quarter Pounder is part of a "classics" menu that drives huge sales. That's why the Golden Arches will want to fix an E. coli issue fast.

McDonald’s said it was taking “swift and decisive action” to control the outbreak that has sickened dozens of people, mainly in Colorado and Nebraska.

The U.S. Centers for Disease Control and Prevention reported the outbreak on Tuesday. It says infections were reported between Sept. 27 and Oct. 11.