McDonald’s E. coli outbreak source identified in US amid rise in cases

US authorities have identified the likely source of an outbreak of E. coli linked to McDonald’s Quarter Pounder sandwiches as the number of cases rises.

The Food and Drug Administration (FDA) said 90 people across 13 states have fallen ill in the outbreak, up from 75 at the end of last week.

The number of people hospitalised increased by five, to 27 people. One death has been tied to the outbreak.

The US Centers for Disease Control and Prevention (CDC) said “fresh, slivered onions are the likely source of illness in this outbreak”.

McDonald’s said the onions came from a single supplier, the California-based Taylor Farms. The company has since recalled the yellow onions it sent to McDonald’s and other restaurant chains.

The FDA said on Wednesday it has begun inspecting Taylor Farms’ processing centre in Colorado Springs as well as an “onion grower of interest” in Washington state. It did not name the grower.

More than 80 per cent of people with E. coli interviewed by government investigators reported eating McDonald’s items containing fresh, slivered onions, the FDA noted.

Officials from the agency said on Wednesday the current risk of illness “is low because the onions have been recalled and should no longer be available”.

They noted that all of the reported cases occurred before Taylor Farms and McDonald’s removed the onions from the market.

McDonald’s said last week that onions from the Colorado Springs facility were distributed to approximately 900 of its restaurants, including some in transportation hubs like airports.

The restaurant chain announced that it would resume serving Quarter Pounders at hundreds of its restaurants after testing ruled out beef patties as the source.

The strain of E. coli behind the outbreak can cause dangerous diarrhoea and lead to kidney failure and other serious problems.

It causes about 74,000 infections in the U.S. annually, leading to more than 2,000 hospitalisations and 61 deaths each year, according to the CDC.