McDonald’s says Quarter Pounders will be sold again after beef patties ruled out as E. coli source CBS NewsNo E. Coli Found in Samples of McDonald’s Beef Patties, Officials Say The New York TimesMcDonald’s E. coli Outbreak Not From Beef Patties. The Quarter Pounder Returns This Week. Barron’sE. coli Outbreak Linked to McDonald’s Quarter Pounders | E. coli infection CDC