More than 100 individuals have reported illnesses connected to an E.coli outbreak linked to slivered onions used in McDonald's Quarter Pounder burgers across the United States, according to the latest findings from health officials. The U.S. Food and Drug Administration (FDA) confirmed on Wednesday that among those affected, 34 were hospitalized, and one man tragically passed away in October.

The outbreak was attributed to onions processed by the supplier Taylor Farms, who recalled their products after the Centers for Disease Control and Prevention (CDC) identified the contaminated onions as the probable source of the ongoing illness. Following this recall, McDonald's swiftly eliminated the onions from its supply chain and temporarily halted the sale of Quarter Pounders at 20% of its restaurants.

Onions linked to the outbreak were reportedly distributed in various states including Colorado, Iowa, and Kansas, with additional cases emerging in Oklahoma, Idaho, and New Mexico. The FDA has since conducted inspections at Taylor Farms' processing facilities and taken environmental samples in an effort to pinpoint the contamination's origin.

While the investigation continues, health officials remain cautious, advising that there does not seem to be ongoing risks to food safety associated with McDonald’s restaurants at this point. Testing has shown that the fast-food giant’s other beef products did not carry the bacteria, allowing them to commence sales of the Quarter Pounders once again after sourcing from a new supplier.

As a response to the outbreak and subsequent consumer anxiety, McDonald's CEO Chris Kempczinski expressed regret over the incident, extending sympathies to those affected and asserting the company's commitment to food safety standards. Legal action has also been initiated by certain consumers against the fast-food chain, including a class-action lawsuit filed in October, as concern over food handling practices continues to unfold.