When a ‘Quarter Pounder’ burger was connected to an E. coli epidemic that killed one person in the United States, McDonald’s stock fell

A ‘Quarter Pounder’ burger from the food giant was connected to an E. coli epidemic that killed one person and affected 49 others in the US, causing McDonald’s shares to drop 7.3% in early trade on Wednesday.

The U.S. Centers for Disease Control and Prevention said Tuesday that the epidemic was recorded in 10 states and that at least 10 individuals were hospitalized. Reports of cases started in late September and lasted into October.

According to McDonald’s preliminary findings, the epidemic may have been brought on by the usage of sliced onions used in the «Quarter Pounder» and originated from a single supplier that supplied three distribution sites.