Public health officials are investigating an outbreak of Escherichia coli O157:H7 infections in 13 states in the USA. As of Oct 30, 2024, 90 cases have been reported, including 27 hospitalisations, two cases of haemolytic uraemic syndrome, and one death. All reported cases have been linked to individuals eating at the fast-food chain McDonald’s. Initially, the contamination was thought to be related to beef patties found in the restaurant’s Quarter Pounders; however, this has now been ruled out and McDonald’s have resumed sales of the product.