The stock of McDonald's lost up to 10 percent of its value after US health authorities linked a deadly E. coli outbreak to the fast-food chain's Quarter Pounder burgers.

The Centers for Disease Control and Prevention (CDC) reported on Tuesday that 49 people in ten states have been affected by a "severe" E. coli outbreak. Ten people were hospitalized, including one child with complications; an elderly person has died. All respondents stated that they had eaten at McDonald's before falling ill.

The focus of the investigations is on fresh, sliced onions and fresh beef patties used in the Quarter Pounders. Initial findings suggest that the onions come from a single supplier that supplies three distribution centers.

McDonald's Responded and Temporarily Suspended the Sale of the Quarter Pounder in Four States, Including Colorado and Nebraska, as well as in Parts of Eight Other States in the Midwest and Southwest USA

The USA is McDonald's largest market with over 13,000 locations. In the fiscal year ending in June, the company generated worldwide sales of nearly 26 billion US dollars. Piña emphasized that McDonald's is working closely with its suppliers to restore the supply of Quarter Pounders in the coming weeks. Other popular burgers like the Big Mac are not affected.

The CDC urged anyone experiencing severe symptoms such as diarrhea, abdominal cramps, vomiting, and fever after consuming a Quarter Pounder to seek medical help and inform their doctor about the consumption. All infected individuals tested positive for the same bacterial strain "O157".

Despite improvements in food safety standards, the CDC estimates that nearly 100,000 people in the USA fall ill each year from E. coli bacteria, resulting in approximately 3,270 hospitalizations and 30 deaths.