The U.S. Centers for Disease Control and Prevention (CDC) reported a serious outbreak of E. coli infections connected to McDonald's Quarter Pounder hamburgers across 10 states.
The outbreak has resulted in the hospitalisation of 10 people, with one elderly individual in Colorado losing their life.
Shares in McDonald's fell by approximately 6.7% in after-hours trading following the announcement.
According to the CDC, all affected individuals reported eating at McDonald's prior to falling ill, with many specifically citing the Quarter Pounder as the meal they consumed.
Investigators are currently focusing on fresh, slivered onions and fresh beef patties as potential sources of the contamination, though the exact cause has yet to be confirmed.
In response, McDonald's has voluntarily removed the suspect slivered onions and beef patties used in Quarter Pounders from stores located in the impacted states while the investigation continues.
The company informed the CDC of these precautionary measures, although it has yet to release an official comment on the situation.
The CDC noted that 49 individuals across 10 states have been affected by the same strain of E. coli, with the majority of cases concentrated in Colorado and Nebraska.
E. coli symptoms can include severe stomach cramps, diarrhoea, and vomiting, which can lead to severe health complications, especially in vulnerable individuals.
The CDC also indicated that Quarter Pounders might be temporarily unavailable in some states until further notice.
At the close on (AEDT) Wednesday October 23, McDonald's stock price (MCD) was US$314.69, experiencing a slight decrease of 0.24% from the previous day. The stock saw a day low of US$313.30 and a day high of US$317.90. It has a market cap of US$225.741 billion. After hours, it was trading around US$293.83, a drop of around 21 points (approx -6.7%).