**McDonald's Quarter Pounder Linked to E. Coli Outbreak Across Multiple States**

McDonald's announced that it has been informed by the Centers for Disease Control and Prevention (CDC) about a potential connection between its Quarter Pounder burgers and an E. coli outbreak. The fast-food giant took preemptive action by retracting the menu item from restaurants in the affected regions prior to the CDC's advisory. This measure impacts approximately 20% of McDonald's outlets in the U.S.

The CDC communicated the preliminary findings to McDonald's late last week, at which point the number of associated cases was notably fewer. As of Tuesday, the CDC has linked 49 cases and one fatality across 10 states to the outbreak, all related to the Quarter Pounder burgers. McDonald's has been collaborating closely with the CDC, the U.S. Department of Agriculture, and the U.S. Food and Drug Administration to probe the issue further.

Detailed investigations by the CDC revealed that out of 18 interviewed patients with confirmed cases, 12 had consumed Quarter Pounder burgers before falling ill. The affected regions include Colorado, Kansas, Utah, Wyoming, and parts of eight additional states. McDonald's Chief Supply Chain Officer for North America, Cesar Pina, confirmed in a statement that they are removing the Quarter Pounders from restaurants in these areas.

The CDC is examining both the onion and beef patty components of the Quarter Pounder. Despite the beef being sourced from multiple suppliers and supposedly cooked to temperatures that should eliminate bacteria, the focus has shifted towards the onions. It was noted that McDonald's in those regions used a single supplier for onions, responsible for washing and slicing the ingredient. Consequently, the company has halted the distribution of the onions and instructed local outlets to discard their existing stock.

The timeline for the reported cases spans from September 27 to October 11, during which McDonald's usually sells around one million Quarter Pounders in the affected areas. In the wake of these developments, McDonald's shares have dropped by 5% in afternoon trading, sparking investor concerns over potential declines in sales for the fast-food titan.