Dozens of Americans are still recovering from a dangerous bacteria found festering in one of McDonald’s most iconic burgers. An E. coli outbreak linked to McDonald’s’ Quarter Pounder has led to nearly 50 reported infections across 10 states and one death. The outbreak, which McDonald’s believes stems from a single, massive onion supplier, comes just months after contaminated Boars Head cold cuts resulted in the largest Listeria outbreak in more than a decade.
Food safety experts told Popular Science this uptick in deadly food safety blunders may stem from a chaotic mix of complicated global supply chains, regulatory sluggishness, and shifting appetites for bacteria-prone pre-prepared foods.
What happened with the Quarter Pounder?
The Centers for Disease Control (CDC) says the first illness linked to the contaminated Quarter Pounders was reported in September. Since then, the tainted burgers have led to at least 10 hospitalizations and one death across at least 10 states. There have been at least 49 E.coli cases linked to the burgers nationwide, though that figure could be larger since some people recover from infections on their own without contacting healthcare authorities. The ages of those reported cases range from 13 to 88 years old.
Most of the illnesses were concentrated in two states: Colorado and Nebraska. McDonald’s massive scale can make pinpointing the origin of these infections difficult, so it’s possible the total number of cases could tick upwards in the days and weeks to come. For perspective, the Associated Press estimates the company has 14,000 stores spread across the country and serves up to 1 million quarter-pounders every two weeks in just the 12 impacted states.
Though an investigation into the outbreak’s root cause is still ongoing, McDonald’s released a statement saying it believes the illnesses are tied to slivered onions used specifically for the quarter pounder. McDonald’s sources those slivered onions from a single provider, Taylor Farms, that serves three distribution centers. On Wednesday, Taylor Farms officially issued a recall of its raw onions products, making the onions theory all the more likely. The fast-food giant has temporarily pulled the burger from restaurants in Colorado, Kansas, Utah, and Wyoming. Quarter Pounders also won’t be served in some stores in Montana, Nebraska, New Mexico, and Nevada. Yum Brands, which oversees Taco Bell, Pizza Hut, and KFC, also released a statement Wednesday saying it would stop selling fresh onions in certain locations “out of an abundance of caution.”
“We are working in close partnership with our suppliers to replenish supply for the Quarter Pounder in the coming weeks (timing will vary by local market),” McDonald’s North America Chief Supply Chain Officer Cesar Piña said in a statement. “In the meantime, all other menu items, including other beef products (including the Cheeseburger, Hamburger, Big Mac, McDouble and the Double Cheeseburger) are unaffected and available.”
What is E. coli and how does it spread?
E. coli, formally named Escherichia coli refers to a bacteria commonly found in the guts of people and animals. Most strains of the bacteria are harmless, but some, notably including Shiga-toxin producing E. coli, can spread through food and water and cause serious illness in humans. The bacteria is often spread to humans after consuming infected animal products or by ingesting produce grown using infected water. E. coli affects around 74,000 people in the US each year, leading to over 2,000 hospitalizations and an estimated 61 deaths. Historically, hamburgers and other ground meat items have been potent vectors for spreading the bacteria because one patty can consist of meat made from many different cows, each of which could have been contaminated.
A CDC investigation into the recent rise in E. coli cases revealed the bacteria found in infected people shared the same DNA despite the fact that its human hosts lived in separate states. The Quarter Pounder was the common thread. That information suggests the bacteria originated from one single source or supplier. In this case, both McDonald’s and regulators seem increasingly confident beef wasn’t responsible since the company cooks its burgers at temperatures high enough to kill the bacteria. That makes the slivered onions the main contender. But even if that’s the case, food safety experts like Consumer Federation of America Director of Food Policy Thomas Gremillion say that still leaves many unanswered questions.
“If it’s the onions, how did they get contaminated with E. coli?” Gremillion wrote in an email to Popular Science. “Were they grown next to a feedlot or other cattle operation? What other retailers or restaurants have received these onions? How widespread is the recall?”
McDonald’s directed us toward this food safety blog post when reached for comment.
“Food at McDonald’s might not be particularly nutritious or safe in terms of long-term consumption, but most of us take for granted that it will not cause acute foodborne illness,” Gremillion added.
McDonald’s outbreak follows a string of dangerous Listeria outbreaks
The McDonald’s E. Coli scare comes just months after contamination at Boars Head facilities led to the single largest Listeria outbreak since 2011. Those cases, first reported by the CDS in July, have resulted in 10 deaths and the hospitalization of at least 59 people across 19 states. Several of those people reportedly died after eating tainted Boars Head liverwurst products. Since then, the company has reportedly recalled 7.2 million pounds of product and shuttered a Jarratt, Virginia manufacturing plant responsible for the tainted meat. Boars Head now faces multiple wrongful death lawsuits.
But the Listeria outbreaks aren’t limited to Boars Head. Just this month TreeHouse Foods, which makes store-name branded waffles for Walmart, Target, and other top retailers, issued a recall after testing at one of its facilities identified potential listeria contamination. BrucePac, a company that specializes in pre-cooked meats, was forced to recall 11.8 million pounds of ready-to-eat poultry products over listeria contamination concerns. Possible Listeria exposure in 2024 has resulted in recalls of spinach, peanuts, and even dog food.
US Food Safety is complicated and under constant pressure from business interests
Experts speaking with Popular Science described a food safety apparatus in the US marred by complicated agency jurisdictions and regulatory gaps. Food safety is broadly split up between the USDA, which oversees meat and poultry, and the FDA which is responsible for vegetables and other foods. Northeastern University Professor and food safety advisor Darin Detwiler told Popular Science this dichotomy could “cause gaps in oversight,” especially in product categories like burgers which often mix both fresh produce and proteins. Detwiler went on to say the vast, sprawling supply chains that have come to dominate much of the modern food supply can create “blind spots” that result in contamination falling through the cracks.
“A single contaminated source can impact hundreds of locations, as seen in nationwide outbreaks,” Detwiler said. “Traceability is often lacking, making it difficult to pinpoint the origin of contamination quickly.”
Food contamination is personal for Detwiler. The professor, who was featured in the Netflix documentary Poisoned, says his 16-month-old toddler died in 1996 after being exposed to E. coli contaminated meat from Jack in the Box.
Regulatory agencies like the FDA are also notoriously underfunded and face pressure from food interest groups to police with a light hand. A 2022 Politico investigation alleged the department was diverting attention away from food in order to prioritize drugs and medicine. Stephen Ostroff, who previously served as the acting commissioner of the FDA, told Politico he believed the agency’s food program was on the back burner.” That report went on to detail how the agency had reportedly failed to set standards for agricultural water intended to keep manure and other pathogen sources out of water used to grow produce. In the meantime, multiple foodborne illnesses traced back to contaminated freshwater produce have occurred. Large food industry groups, meanwhile, regularly pressure the FDA and USDA to allow for more self-policing regarding food safety.
In a statement, an FDA spokesperson told Popular Science the US food supply remains one of the safest in the world.
“Our ultimate goal is for the industry to do their part to ensure that the foods they introduce into the market are not adulterated or misbranded,” the spokesperson said. “Recalls help get the food off of the market quickly when something goes wrong and the occurrence of recalls means that manufacturers, importers, and distributors are monitoring for issues and taking action when they detect a problem.”
Changing diets and improved detection could also be driving up recalls
But regulatory challenges might not tell the whole story when it comes to the recent spat of bacteria outbreaks. Americans are eating more and more pre-prepared, “ready-made meals” than before, a trend possibly accelerated by the pandemic-era lockdowns. Those ready-made meals can include frozen meat products that can spend weeks or months in refrigerators and freezers. Detwiler says those cool environments and long shelf lives could give Listeria more time to grow. Sanitation lapses at manufacturing plants or a failure to maintain strict temperature controls can increase the risk of outbreaks even further.
“If there are breakdowns in cold chain management (the process of keeping food at the right temperature from production to consumption), Listeria can multiply in foods that should be kept cold,” Detwiler said.
At the same time, Detwiler says advances in testing technologies like whole genome sequencing mean overseers may be getting better at detecting signs of listeria earlier, which in turn, results in more recalls. In other words, it’s possible that increased recalls may actually be, at least in part, a byproduct of improved bacteria detection. Gremillion agreed and said recalls when detected early, can be success stories.
Gremillion said the recent deadly outbreaks at McDonald’s and Boars Head are grim reminders that even though food safety standards improve in some respects it’s important for consumers and regulators to keep their guards up. Lengthier, hotter summers, he notes, could also increase the risk of contamination in food facilities by bugs and pests.
“There are always food-born illness outbreaks coming up,” Gremillion said. “They never really go away.”
