McDonald's E. Coli outbreak: What we know as nearly 50 people sickened across 10 states

A multistate McDonald's E. Coli outbreak has the Chicago-based burger chain pulling certain ingredients from some menus after 49 people across 10 states were sickened, the Centers for Disease Control and Prevention said Tuesday.

At least 10 of those sickened were hospitalized, the CDC said, including one person that developed a syndrome that led to kidney failure. One death was also reported.

"This is a fast-moving outbreak investigation," an alert from the CDC said. "Investigators are working quickly to confirm which food ingredient is contaminated."

According to the CDC, illnesses were reported between Sept. 27, 2024 to Oct. 11, 2024, in a range of people from ages 13 to 88.

Officials also said that the true number of sick people in the outbreak is "likely much higher than the number reported," and that 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," the CDC said. "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."

As of Wednesday, no illnesses were reported in Illinois, though they were reported in surrounding Midwestern states.

As the E. coli outbreak continues, here's what we know so far, including what ingredients have been pulled from menus, and in which states people got sick.

Which states have McDonald's E. coli outbreaks?

The McDonald's E. coli outbreak has been reported in at least 10 states so far, with the majority of those sickened in Colorado. Here's the full list of states where people have been sickened, according to the CDC:

• Oregon - 1
• Montana - 1
• Utah - 4
• Wyoming - 4
• Colorado - 26
• Nebraska - 9
• Kansas -1
• Missouri - 1
• Iowa - 1
• Wisconsin 1

Of the 49 people sickened, at least 10 were hospitalized, the CDC said, including one person who developed hemolytic syndrome, a serious condition that can cause kidney failure.

One person, an older adult from Colorado, died from the outbreak, the CDC said.

Which menu items is the E. Coli outbreak linked to?

Investigators were working to determine the source of the outbreak, which so far centers on two ingredients, the CDC said: fresh, slivered onions, or beef patties used in Quarter Pounder burgers. The CDC added that most people sickened reported eating Quarter Pounders from the chain.

According to officials, the Food and Drug Administration was "working quickly" to determine if the onions were the source of the outbreak, and to determine if the onions had been served or sold at other businesses. The Food Safety Inspection Service said it was conducting a "traceback" to determine if ground beef was the source of the illness.

As a result, McDonald's pulled ingredients for these burgers from menus in certain states.

In a statement, McDonald's said it was "temporarily removing the Quarter Pounder from restaurants in the impacted area," including in portions of the following states:

• Colorado
• Kansas
• Utah
• Wyoming
• Idaho
• Iowa
• Missouri
• Montana
• Nebraska
• Nevada
• New Mexico
• Oklahoma

The CDC also noted that quarter pound beef patties are only used on the chain's Quarter Pounders.

CNBC reported there have been several past reported cases of E. coli at McDonald's restaurants. In 2022, at least six children developed symptoms consistent with E. coli poisoning after eating McDonald's' Chicken McNuggets Happy Meals in Ashland, Alabama. Four of the six children were admitted to a hospital after experiencing severe adverse effects.

Read McDonald's full statement

McDonald's released a statement about the outbreak Tuesday. Joe Erlinger, McDonald's president, will be live on the TODAY show beginning at 7 a.m. Wednesday to provide an update.

The full statement McDonald's released can be found below.

"Across the McDonald’s System, serving customers safely in every single restaurant, each and every day, is our top priority and something we’ll never compromise on.

It is why we are taking swift and decisive action following an E. Coli outbreak in certain states. The initial findings from the investigation indicate that a subset of illnesses may be linked to slivered onions used in the Quarter Pounder and sourced by a single supplier that serves three distribution centers. As a result, and in line with our safety protocols, all local restaurants have been instructed to remove this product from their supply and we have paused the distribution of all slivered onions in the impacted area.

Out of an abundance of caution, we are also temporarily removing the Quarter Pounder from restaurants in the impacted area, including Colorado, Kansas, Utah and Wyoming, as well as portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico, and Oklahoma. We take food safety extremely seriously and it’s the right thing to do. Impacted restaurants are receiving a stock recovery notice today and should reach out to their field supply chain manager or distribution center with any questions.

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). 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. We will continue to work with the Centers for Disease Control and Prevention (CDC) and are committed to providing timely updates as we restore our full menu."

Symptoms to watch for

The CDC urged anyone who experiences E. coli symptoms after eating at McDonald's to call their healthcare provider.

According to the CDC, most people infected with E. coli experience severe stomach cramps, diarrhea, and vomiting. Symptoms typically appear within three to four days of ingesting the bacteria, and most people recover between five and seven days.

Symptoms include:

• 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

Some people may also develop serious kidney problems known as hemolytic uremic syndrome, or HUS, which requires hospitalization. The CDC noted that at least one child experienced that symptom in connection with this outbreak.

What is E. coli?

According to the Mayo Clinic, E. coli stands for Escherichia coli, a bacteria that normally lives "in the intestines of healthy people and animals."

"Most types of E. coli are harmless or cause relatively brief diarrhea. But a few strains ... can cause severe stomach cramps, bloody diarrhea and vomiting," the clinic reported.

People can be exposed to the bacteria from contaminated water or food, particularly raw vegetables or undercooked ground beef.