Key Points:
- 49 people from 10 states have gotten sick from the same strain of E. coli O157:H7. Most sick people are from Colorado (27) or Nebraska (9).
- 10 people have been hospitalized. One older person in Colorado has died. Additionally, one child is hospitalized with complications of hemolytic uremic syndrome, or HUS.
- Everyone interviewed has reported eating at McDonald’s before their illness started, and most specifically mentioned eating a Quarter Pounder hamburger.
- The specific ingredient linked to illness has not yet been identified, but investigators are focused on two ingredients in particular: fresh slivered onions, and fresh beef patties.
- McDonald’s reported to CDC that they proactively removed the slivered onions and beef patties used for the Quarter Pounder hamburgers from stores in the affected states while the investigation continues. Quarter Pounder hamburgers in some states may be temporarily unavailable.
October 23, 2024
Washington, DC, (Highpoint Digest) − On October 22, 2024, CDC, FDA, USDA FSIS, and public health officials in multiple states are investigating an outbreak of E. coli O157:H7 infections. Most people in this outbreak are reporting eating the Quarter Pounder hamburger at McDonald’s before becoming sick. It is not yet known which specific food ingredient is contaminated.
Epidemiologic data show that Quarter Pounder hamburgers served at McDonald’s are contaminated with E. coli and are making people sick. Early information from FDA indicates onions may be a source of this outbreak. Investigators from all agencies are working quickly to determine the contaminated ingredient.
Epidemiologic data
As of October 22, 49 people infected with the outbreak strain of E. coli O157:H7 have been reported from 10 states. Illnesses started on dates ranging from Sept 27, 2024, to October 11, 2024. Of 28 people with information available, 10 have been hospitalized, and 1 person developed hemolytic uremic syndrome, a serious condition that can cause kidney failure. One death has been reported from an older adult in Colorado. This is not the same person with HUS.
The true number of sick people in this outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for E. coli. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.
Public health officials collect many different types of information from sick people, including their age, race, ethnicity, other demographics, and the foods they ate in the week before they got sick. This information provides clues to help investigators identify the source of the outbreak.
The table below has information about sick people in this outbreak (“n” is the number of people with information available for each demographic).
State and local public health officials are interviewing people about the foods they ate in the week before they got sick. Of the 18 people interviewed, all 18 (100%) report eating at McDonald’s, and 16 people report eating a beef hamburger. Of 14 people who remember the specific beef hamburger they ate at McDonald’s, 12 (86%) report eating a Quarter Pounder hamburger. Some people in this outbreak reported traveling to other states before their illness started. At least one person ate at McDonald’s during their travel.
Traceback Information
Investigators are working to determine if the slivered onions or beef patties in Quarter Pounder burgers are the specific source of this outbreak.
Preliminary traceback and distribution information reviewed by FDA shows that slivered onions served on Quarter Pounders are a likely source of contamination. FDA is working quickly to confirm that these onions are a source of this outbreak and to determine if these onions were served or sold at other businesses.
FSIS is conducting traceback on hamburger patties served at McDonald’s to determine if ground beef is a source of illness.
Public health actions
McDonalds has stopped using fresh slivered onions and quarter pound beef patties in several states to protect their customers while a source of illness is confirmed. Quarter Pounders will not be available for sale temporarily in some states. Call your healthcare provider if you ate a McDonald’s Quarter Pounder hamburger and have severe E. coli symptoms.
In Summary
McDonald’s is collaborating with investigation partners to determine what food ingredient in Quarter Pounders is making people sick. McDonald’s stopped using fresh slivered onions and quarter pound beef patties in several states while the investigation is ongoing to identify the ingredient causing illness.
Contaminated food
McDonald’s Quarter Pounder hamburgers are making people sick, with most illnesses in Colorado and Nebraska.
- Quarter Pounder hamburgers will not be available temporarily in some states.
- Investigators are working to confirm which ingredient in these hamburgers is making people sick and if it went to other restaurants or stores.
- McDonald’s reported to CDC that it has stopped using fresh slivered onions and quarter pound beef patties in several states. McDonald’s is proactively making these changes while investigators work to confirm the contaminated ingredient. Quarter pound beef patties are only used on Quarter Pounders. Fresh slivered onions are primarily used on Quarter Pounder hamburgers and not other menu items.
What you should do
McDonald’s has stopped using fresh slivered onions and quarter pound beef patties in several states to protect their customers while a source of illness is confirmed.
Call your healthcare provider if you ate a McDonald’s Quarter Pounder hamburger and have severe E. coli symptoms:
- Diarrhea and a fever higher than 102°F
- Diarrhea for more than 3 days that is not improving
- Bloody diarrhea
- So much vomiting that you cannot keep liquids down
- Signs of dehydration, such as:
- Not peeing much
- Dry mouth and throat
- Feeling dizzy when standing up
Symptoms of E. coli
- Most people infected with Shiga toxin-producing E. coli experience severe stomach cramps, diarrhea (often bloody), and vomiting.
- Symptoms usually start 3 to 4 days after swallowing the bacteria.
- Most people recover without treatment after 5 to 7 days.
- Some people may develop serious kidney problems (hemolytic uremic syndrome, also called HUS) and would need to be hospitalized.
McDonald’s North America Chief Supply Chain Officer Cesar Piña recently shared the following internal message.
Always Putting Food Safety First
October 22, 2024
Source: CDC, FDA, FSIS, USDA
