Health authorities are investigating an outbreak of E coli infections linked to McDonald’s Quarter Pounder cheeseburgers in 12 states in the US midwest and mountain west.
At least 75 people have been sickened, 22 people hospitalized and one died, according to the Centers for Disease Control and Prevention (CDC). While the investigation is ongoing, here’s what authorities currently know about how people might have been sickened and what to do about it.
How did people get sick from cheeseburgers?
The cause of the outbreak is not known, but a McDonald’s Quarter Pounder has two ingredients that are most likely to make people sick: a fresh beef patty and fresh onions.
Meat can carry food-borne illness when it is contaminated during processing or when it comes into contact with contaminated equipment, like a meat grinder. Ground beef is especially susceptible to this kind of contamination because bacteria are distributed throughout the meat – not just on the surface. That makes it more difficult to destroy the bacteria during cooking.
Wait, onions can make me sick?
Fresh sliced onions are also a potential culprit in this outbreak because, unlike beef patties, which are typically cooked, sliced onions are served raw. That means there is no cooking chance to kill the bacteria with heat. The Quarter Pounder burger item on a McDonald’s menu is served with raw onion.
Fresh vegetables have been to blame in several recent E coli outbreaks. For instance, an FDA report found cattle grazing near fields of lettuce in California’s Salinas valley probably caused three E coli outbreaks in 2019. An irrigation canal in Yuma, Arizona, that linked a feedlot with tens of thousands of animals to a romaine lettuce field probably caused a different outbreak in 2018 – at the time it was the largest outbreak in a decade.
The US Department of Agriculture has already said that fresh onions are probably the cause of the McDonald’s outbreak, even as the CDC continues to investigate. The source of the onions, Taylor Farms, has contacted stores that carry its products to notify them of a recall. Taylor is one of the largest food service suppliers in the country.
How do I know if I have E coli?
Escherichia coli, commonly known as E coli, is a common bacteria that lives in the guts of animals and people alike. Most E coli bacteria do not make people sick but some strains can, specifically those that produce shiga toxins.
Shiga toxin-producing E coli disrupts the body’s normal functioning in many ways, from inhibiting normal protein production to causing immune responses in the kidneys, intestines and central nervous system.
Symptoms usually appear within three to four days of consuming E coli bacteria and most people recover within five to seven days. You should contact a doctor if you have severe symptoms such as intense stomach cramps, extreme and even bloody diarrhea, and vomiting. Children and older adults are most susceptible – in children that includes life-threatening kidney failure, and clotting disorders in adults.
What can I do to avoid getting sick?
Businesses should not use onions that have been recalled from Taylor Farms. McDonald’s has stopped using fresh sliced onions and quarter-pound ground beef patties in states where the outbreak has been reported. Rivals Taco Bell, Burger King and KFC have also stopped using fresh onions.
In your home, health authorities additionally recommend cooking food to 160F (71C) to destroy E coli – that includes both ground beef and onions.
It is hard to prevent E coli in vegetables that are generally served raw, such as leafy greens (not implicated in this outbreak) because washing vegetables is not shown to remove E coli bacteria. The best way to avoid getting sick is to avoid suspect food altogether during outbreaks.
How else can I protect myself?
Eating food contaminated with E coli can easily get you sick, but it is not the only way.
E coli can spread when people are exposed to infection by another person, such as through changing diapers. E coli outbreaks have also occurred when people came into contact with goose feces in lake water.
Wash your hands – especially after going to the bathroom, dealing with pets or being outdoors. Drink safe water and practice safe food handling.
