An E. coli outbreak linked to McDonald's Quarter Pounders sold at locations across the United States has sickened at least 75 people, landed 22 in the hospital and caused one death. Cases have been reported in 13 states so far, with the most illnesses in Colorado and Montana.
On Tuesday, the U.S. Centers for Disease Control and Prevention posted a food safety alert announcing it was investigating a multi-state outbreak of E. coliO157:H7 infections linked to contaminated McDonald's Quarter Pounders. The Food and Drug Administration, the U.S. Department of Agriculture and state health officials are also investigating.
The CDC called the outbreak "severe" in a press release, adding that McDonald's has temporarily removed the suspected ingredients at select locations. Officials have not yet confirmed the source of the outbreak, but investigators are zeroing in on fresh slivered onions served on the Quarter Pounders.
Escherichia coli(E. coli) is bacteria found in the intestines of humans and animals. Some types, like E. coli O157:H7, can produce powerful toxins that can cause severe and potentially deadly illness. Symptoms can include bloody diarrhea, severe stomach cramps and vomiting.
McDonald's E. coli outbreak 2024
At least 75 cases of E. coli have been reported in 10 states so far, which is up from 49 reported on Oct. 22, but "the true number of sick people is likely much higher," the CDC said.
Everyone interviewed as part of the investigation reported eating a McDonald's burger before developing symptoms, with most specifically mentioning Quarter Pounders.
In a statement released on Oct. 22, McDonald's said it was taking “taking swift and decisive action.”
Quarter Pounders are temporarily unavailable for purchase at McDonald’s stores in 12 states, per the CDC, and investigators are working to determine which specific ingredients are contaminated with E. coli.
Two ingredients used in Quarter Pounders are currently being investigated: fresh slivered onions and quarter-pound beef patties, the CDC said. Preliminary data suggests the fresh onions are a "likely source" of contamination, the FDA said.
A McDonald's spokesperson told NBC News that the onions in question come from a single source and get sliced and packaged in individual bags at a facility before being sent to restaurants.
Taylor Farms, a California-based producer with distribution facilities across the country, has been identified as the supplier of the onions to McDonald's locations involved in the outbreak.
Distributor U.S. Foods announced Oct. 23 that Taylor Farms in Colorado has recalled whole and diced yellow onions out of an abundance of caution “due to potential E. coli contamination.”
Taco Bell, Burger King, KFC and Pizza Hut have also removed fresh onions from the menu at select locations, a spokesperson for parent company YUM! Brands confirmed to TODAY.
The FDA is probing whether the McDonald’s outbreak can be traced directly back to onions from Taylor Farms, but an FDA spokesperson said the agency is “looking at all possible sources.”
Joining TODAY on Oct. 23, McDonald's USA President Joe Erlinger addressed the outbreak, stating that consumers can "confidently go to McDonald’s today" and eat the classics without getting sick.
“Food safety is our top priority at McDonald’s," Erlinger said.
McDonald’s E. coli outbreak states affected
The outbreak has affected 13 states so far, with Colorado reporting the highest number of cases, followed by Montana and Nebraska, according to the latest data from the CDC.
States affected and number of illnesses reported:
- Colorado: 26
- Montana: 13
- Nebraska: 11
- Utah: 5
- New Mexico: 5
- Missouri: 4
- Wyoming: 4
- Michigan: 2
- Wisconsin: 1
- Iowa: 1
- Kansas: 1
- Oregon: 1
- Washington: 1
"This outbreak may not be limited to the states with known illnesses, and the true number of sick people is likely much higher than the number reported," the CDC said on its website.
If you have questions about specific cases in your state, contact your state's department of health, the CDC advised in a press release.
States where McDonald's has taken Quarter Pounders off the menu
As the outbreak investigation continues, McDonald's stores in multiple states have temporarily stopped selling Quarter Pounder beef patties and fresh slivered onions.
The quarter-pound patties are only used on Quarter Pounders, and the slivered onions are "primarily used on Quarter Pounders and not other menu items," the CDC said.
McDonald’s stores in the following states (or portions of states) have temporarily removed Quarter Pounders from their menus:
- Colorado
- Kansas
- Utah
- Wyoming
Portions of:
- Idaho
- Iowa
- Missouri
- Montana
- Nebraska
- Nevada
- New Mexico
- Oklahoma
One person has died, 22 hospitalized
There has been one death of an older adult in Colorado due to the outbreak. At least 22 people have been hospitalized, up from 10 reported on Oct. 22, including one child who has developed hemolytic uremic syndrome (HUS), a serious condition that can lead to kidney failure, the CDC said.
The people sickened range in age from 13 to 88.
The illnesses linked to this outbreak started between Sept. 27, 2024 and Oct. 11, 2024. It’s also possible that there are more recent illnesses that have yet to be reported, since it can take three to four weeks to link an individual’s sickness to an outbreak, per the CDC.
The CDC said it was first alerted to E. coli cases in Colorado almost two weeks ago.
“We do expect the number of illnesses to go up,” Dr. Matthew Wise, chief of the CDC’s outbreak response and prevention branch, said in a TODAY show interview aired Oct. 24. “We think that’s going to be driven by people who ate Quarter Pounders at McDonald’s before they took these actions.”
Two lawsuits have been filed against McDonald’s in connection to the outbreak. One of these plaintiffs, Clarissa DeBock of Nebraska, told NBC News she tested positive for E. coli after going to the emergency room for severe gastrointestinal symptoms, which she attributes to a Quarter Pounder she ate the week prior.
DeBock, 33, described her symptoms as “miserable” and is seeking compensation for medical bills, lost wages, as well as physical and emotional suffering, NBC News reported.
Is McDonald's safe to eat?
Yes, McDonald's is safe to eat, according to Erlinger.
“We are very confident that you can go to McDonald’s and enjoy our classics,” he said on TODAY.
All other menu items and burgers (including the cheeseburger, hamburger, Big Mac, and McDouble) “are unaffected and available,” McDonalds said in its statement.
There are two types of onions used in McDonald's menu items in the U.S. In addition to the fresh slivered onions used on Quarter Pounders, McDonald's also uses diced, dehydrated onions, which have been rehydrated with water. The diced rehydrated onions are not currently being investigated in this outbreak, according to U.S. health officials.
What is E. coli?
E. coli is a type of bacteria found in the environment, food, water, and in the digestive tract of humans and animals, per the CDC. While most types of E. coli are harmless or cause mild diarrhea, some types can cause severe disease.
Certain strains, such as E. coli O157:H7, can produce powerful Shiga toxins that can cause life-threatening illness. The most common Shiga toxin-producing E. coli (STEC) strain in the U.S. is E. coli O157:H7, which is the one involved in the McDonald's Quarter Pounder outbreak.
E. coli O157:H7 causes an an estimated 73,000 illnesses per year in the U.S.
How do you get E. coli?
People can be exposed to E. coli by eating or drinking contaminated food or water. The primary food sources of Shiga-producing E. coli outbreaks are raw or undercooked ground beef, raw vegetables and raw milk or cheese, according to the FDA.
In the case of ground beef, it can become contaminated if the E. coli bacteria living in the intestines of cattle accidentally ends up on other cuts of meat during the slaughter process, which all get ground up together, Donald Schaffner, Ph.D., professor and chair of the Department of Food Science at Rutgers University, told NBC News.
As for vegetables, such as onions, these could become contaminated if they are grown nearby cattle or if cattle manure is used as compost, Schaffner added.
Transmission can also occur through touching an infected person’s feces or contaminated surfaces, per the Cleveland Clinic. This may result from poor hygiene after using the bathroom, changing diapers and before eating.
Some people are more likely to be infected with E. coli, according to the CDC. These include children under the age of 5, adults 65 and older, people with weak immune systems and international travelers.
E. coli symptoms
Typically, symptoms start three to four days after swallowing the bacteria from contaminated food, per the CDC. However, the incubation period can range from one to 10 days.
Symptoms of infection with E. coli O157:H7 include:
- Stomach cramps, which can be severe
- Bloody or watery diarrhea
- Vomiting
- Low fever
There is no specific treatment for E. coli infections. Most people can be treated symptomatically with supportive care, such as fluids and rest, per the CDC.
Can E. coli kill you?
Yes. While, most people who get sick with E. coli will recover on their own within a week, per the CDC, some people can develop dehydration or life-threatening complications, including hemolytic uremic syndrome, which can lead to kidney failure or death.
Symptoms of HUS include urinating less frequently or not at all, pale skin, irritability, weakness, dizziness and bruising easily, per the Mayo Clinic.
Young children, the elderly and people with weak immune systems are at greater risk of developing life-threatening complications from an E. coli infection.
The CDC urges anyone who has eaten a Quarter Pounder from McDonald's recently and experienced severe symptoms to call their health care provider.
If you experience signs of dehydration (decreased urination, dry mouth, dizziness), severe vomiting, bloody stools or a fever over 102 degrees Fahrenheit, seek immediate medical attention and tell the health care provider what you ate.
Caroline Kee
Caroline Kee is a health reporter at TODAY based in New York City.