McDonald’s hit as Quarter Pounders tied to US E. coli outbreak

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Shares in McDonald’s dropped by as much as 10 per cent after US public health authorities linked a fatal E. coli outbreak affecting 10 states with the fast-food chain’s Quarter Pounder hamburgers.

The Centers for Disease Control and Prevention said on Tuesday that the “severe” E. coli outbreak had infected 49 people, leaving 10 in hospital and one elderly person dead. Everyone interviewed by authorities investigating the outbreak reported having eaten McDonald’s before falling ill.

The health agency said the outbreak appeared to be connected with consumption of McDonald’s signature Quarter Pounder, with investigations focusing on fresh, slivered onions and fresh beef patties as the ingredients suspected of having been contaminated.

In after-market trading, shares in McDonald’s fell by as much as 9.6 per cent, cutting as much as $20bn from its market value, before recovering to trade 5.6 per cent lower.

Most people affected by the outbreak were in the US states of Colorado and Nebraska, the CDC said. McDonald’s said it had temporarily withdrawn the sale of Quarter Pounders in four states, including Colorado, as well as parts of eight other states across the Midwest and southwestern US.

“We take food safety extremely seriously and it’s the right thing to do,” said McDonald’s North America supply chain officer Cesar Piña of its decision to pull the products from the shelves, explaining that the chain had made the move “out of an abundance of caution”.

Early findings from the investigation connected the outbreak with slivered onions sourced from a single supplier, which serves three distribution centres, explained Piña.

The US is McDonald’s biggest market, with more than 13,000 managed and franchised stores. The fast food group generated almost $26bn in worldwide sales in the year to the end of June.

Piña added that McDonald’s was “working in close partnership with our suppliers to replenish supply for the Quarter Pounder in the coming weeks”, pointing out that other popular burgers including the Big Mac were unaffected.

One of the 10 people hospitalised due to the outbreak was a child suffering from complications from E. coli infection, the CDC said.

Those infected as part of the outbreak all tested positive for the same strain of the bacteria, known as “O157:H7”. The CDC called on anyone suffering from severe symptoms after eating a Quarter Pounder, including diarrhoea, stomach cramps, vomiting and fever, “to seek healthcare and tell your provider about what you ate”.

Improvements in food safety standards have helped to stamp out E. coli outbreaks in the US but the CDC still estimates that nearly 100,000 people fall ill with the bacteria each year, resulting in an estimated 3,270 hospitalisations and 30 deaths.

Most recently, the CDC was monitoring outbreaks of strains of E. coli linked to organic walnuts sold at natural food stores in California and Washington, as well as another outbreak linked to the Raw Farm cheddar cheese brand.

In 2022, rival fast-food chain Wendy’s took the precautionary measure of removing Romaine lettuce from its burgers and sandwiches after the CDC investigated the ingredient in connection with an E. coli outbreak, which left more than 100 people sick across six states. The agency never established whether contaminated lettuce was the source of the outbreak.