In the wake of a troubling E. coli outbreak linked to contaminated onions, McDonald’s has temporarily removed its Quarter Pounder from the menu across approximately 20% of its 14,000 locations in the U.S. This incident has highlighted a recurring nightmare for restaurant operators: the reality that fresh produce can be far more prone to contamination than beef.
On October 23, the U.S. Department of Agriculture (USDA) identified onions as a potential source of the E. coli outbreaks affecting McDonald’s restaurants in the Midwest and some Western states. The outbreak has resulted in 49 reported illnesses and one death.
In recent years, beef has been the primary source of foodborne illness outbreaks, leading federal health regulators to tighten their scrutiny of beef contamination. Previously, a related E. coli outbreak linked to Jack in the Box burgers resulted in over 170 hospitalizations and four deaths across several states. Experts note that outbreaks associated with beef have become increasingly rare.
The key distinction, experts say, is that beef is cooked, whereas fresh produce is typically consumed raw. “Correct cooking practices are the ultimate remedy for preventing contamination,” stated Dr. Donald Schaffner, a food science and safety expert at Rutgers University.
While large-scale agricultural products undergo rigorous washing, disinfection, and testing, the ability to detect minimal contamination levels remains a significant challenge. Crops are usually grown outdoors, where wildlife or nearby farm animals can introduce fecal pathogens into irrigation water or floodwaters. E. coli is a standard pathogen found in animal intestines.
Schaffner noted that contamination could occur from using untreated manure or contaminated irrigation water, or even from improper handling and slicing of onions.
Similar stringent testing protocols that apply to beef are also expected for agricultural products, and fast-food chains alongside other buyers frequently demand such measures. However, as stated by expert Samad Dehghani, “The cleaner the product, the tougher it is to detect.”
A spokesperson for McDonald’s indicated that their suppliers routinely test products and in accordance with the timeline provided by the Centers for Disease Control and Prevention (CDC) during the outbreak, none of the suppliers reported finding this specific strain of E. coli.
In 2022, the CDC identified lettuce as the likely source of an E. coli outbreak that sickened dozens, prompting several Wendy’s locations to remove lettuce from their menus. Similarly, in 2006, contaminated lettuce from Taco Bell, a subsidiary of Yum Brands, was implicated in an E. coli outbreak that led to 71 illnesses.
