A severe outbreak of E. Coli linked to McDonald’s Quarter Pounder burgers has expanded to 75 reported cases, mainly in the western United States, authorities said on Friday.
The number of hospitalisations has risen to 22, though no additional deaths have been reported beyond that of an elderly patient in Colorado, according to the Food and Drug Administration (FDA) and the Centres for Disease Control and Prevention (CDC).
One child and one adult developed haemolytic uremic syndrome, a serious condition that damages blood vessels in the kidneys.
Investigators have yet to confirm a specific ingredient as the contamination source, though they are assessing whether slivered onions or beef patties could be the origin.
While the investigation is underway, Taylor Farms, which supplies the slivered onions to affected locations, has issued a voluntary recall of its yellow onions.
McDonald’s restaurants in the 13 impacted states have temporarily pulled Quarter Pounders from their menus, though other items, including other beef burgers, remain available.
Shares of the fast-food giant dropped more than 2% in early afternoon trading.
Meanwhile, the law firms Ron Simon & Associates and Meyers & Flowers have filed lawsuits on behalf of two separate consumers from Colorado and Nebraska who fell ill after consuming the burgers.
Each suit seeks a minimum of $50,000 in damages, and attorney Ron Simon told AFP that he plans to represent a total of 25 victims.
“When a consumer goes to McDonald’s to buy a meal, they’re placing an enormous amount of trust that McDonald’s has done everything it can to make your food safe,” said Simon. “And here, whether it was faulty testing, faulty oversight, faulty handling, somehow poison got in that food, and trust is broken.”
The CDC advised those who consumed a Quarter Pounder and developed symptoms of E. coli poisoning – such as diarrhoea, bloody diarrhoea, a fever over 102° Fahrenheit (38.9°C), and vomiting – to seek medical attention.
Symptoms typically begin 3-4 days after exposure, and most individuals recover within five to seven days without treatment.
However, some cases can become severe and require hospitalisation.
McDonald’s said in a statement on Tuesday that it had taken “swift and decisive action” and that food safety was its “top priority”.
In past years, beef patties dominated the dockets of foodborne illness lawyers, before US federal health regulators cracked down on beef contamination after an E. coli outbreak linked to Jack in the Box burgers hospitalised more than 170 people across states and killed four.
As a result, beef-related outbreaks became much rarer, experts say.
“Produce is a much harder problem,” said Mike Taylor, a lawyer who played leadership roles in safety efforts at the FDA and the US Department of Agriculture, and today is on the board of a nonprofit called STOP Foodborne Illness.
Experts say the biggest difference is that beef is cooked while fresh produce, by definition, is not cooked.
Proper cooking is a “silver bullet” against contamination, said Donald Schaffner, a Rutgers University food science and safety expert.
Large-scale industrial produce is washed, sanitised and tested to a similar degree that beef is, but tests cannot catch sufficiently low levels of contamination, experts say.
Crops are often grown outdoors, where faeces from wildlife or nearby agricultural animals can seep into irrigation water or floodwater.
E. coli is a normal pathogen in the guts of animals.
Cattle have it more than others, but it has also been detected in geese, boars, deer and others, said Mansour Samadpour, a food safety specialist.
Contamination could arise from using untreated manure or contaminated irrigation water, or from holding or slicing the onions in a way where they became contaminated, Schaffner said.
Both McDonald’s and Taylor Farms, a supplier of yellow onions to McDonald’s in the affected states, are large and sophisticated companies, and widely regarded by food safety experts as standard-bearers for safe practices.