McDonald's e. What we know about the investigation of the coli outbreak CNN

An e associated with McDonald's Quarter Pounders. coli outbreak has caused at least 49 illnesses, including one death, in 10 states.

Here's what we know.

The U.S. Centers for Disease Control and Prevention issued a food safety alert Tuesday warning that dozens of people have reported eating quarter-pounder sandwiches at McDonald's before becoming ill.

A specific ingredient has not been confirmed as the source of the outbreak, but the US Food and Drug Administration says slivered onions or beef patties in quarter pounder sandwiches are possible sources of contamination.

McDonald's has removed the Quarter Pounder from the menu in about a fifth of its stores. The company has stopped using the quarter-pound beef patty alongside onions in several states — Colorado, Kansas, Utah and Wyoming, as well as parts of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico and Oklahoma — while the investigation continues. The CDC said.

According to the company, the beef patties are used only for the quarter pounder and the slivered onions are used primarily for the quarter pounder and not other items. The FDA said onion and other types of beef patties used at McDonald's have not been linked to the outbreak.

Escherichia coli, or E. coli, is a common bacteria, but certain types can make you sick. Infection can occur after someone swallows the bacteria, often when contaminated food or water is consumed. It can also spread from person to person through poor bathroom hygiene.

People with E. coli infections may have symptoms including severe abdominal pain, diarrhea, fever, and vomiting. Symptoms usually begin three or four days after swallowing the bacteria.

Although most people who become ill recover without treatment within a week, others may develop serious kidney problems and require hospitalization. According to the CDC, the elderly, children under 5, and people with weakened immune systems are most at risk of infection.

E. of new outbreaks. coli infection resulted in at least 10 hospitalizations, the CDC said, including a child who had hemolytic uremic syndrome, a serious complication caused by E. Can develop from coli infection An old man died.

According to the CDC, most of the illnesses associated with the outbreak are in Colorado and Nebraska, but the agency notes that the outbreak may extend beyond those states. Illnesses have also been reported in Iowa, Kansas, Missouri, Montana, Oregon, Utah, Wisconsin and Wyoming.

The CDC recommends that people who have recently eaten a McDonald's Quarter Pounder and have severe E. coli causes symptoms such as fever over 102 and diarrhea, especially bloody diarrhea or diarrhea that has not improved in three days, vomiting. Limits fluid intake or signs of dehydration.

It may take weeks to determine whether an illness is part of an outbreak, but the CDC said the investigation into the McDonald's outbreak is “rapidly-moving.”

The agency said outbreaks are expected to increase, with new cases being reported “on a rotating basis” as scientists make genetic links between outbreak strains and the bacteria that cause human infections.

According to CDC data, outbreak-related illnesses were reported from September 27 to October 11. But the start date of the outbreak could change as cases come to light, according to an official with knowledge of the investigation.

Such outbreaks can decrease rapidly even after the contaminated food or ingredient is removed from the market. This requires a thorough investigation to ensure that all possible channels of distribution are uncovered and closed.

The president of McDonald's USA said it is safe to eat at McDonald's and that the affected ingredients are likely out of the supply chain at the restaurants.

“We're very confident that you can go to McDonald's and enjoy our classics” without getting sick, McDonald's USA President Joe Erlinger said Wednesday on NBC's “Today Show.”

Quarter pounder sandwiches will be temporarily removed from the menu in some states while the company changes supplies, according to the CDC.

Erlinger said he believes that “if there is contaminated product in our supply chain, it probably worked its way through that supply chain,” but he acknowledged that the number of reported illnesses could increase as the CDC investigates and identifies cases.

“Serving customers safely at every restaurant is our highest priority,” McDonald's said in a statement Tuesday.

A fact sheet from the agency highlights food safety protocols it says include daily temperature checks and hourly hand washing for workers. It also notes that quarter pounders are best practices cooked to temperatures that exceed the FDA's code.

CDC data released this summer show that foodborne illness is on the rise in the United States. E. Some illnesses, including coli infections, far exceed federal targets for reducing foodborne illness.

More than 5 E. per 100,000 people in the United States in 2023. coli, which is a 25% increase over five years ago and almost 40% higher than the target rate.

Campylobacter bacteria is the most common pathogen that causes foodborne illness, causing more than 19 illnesses per 100,000 people – a rate that is 22% higher than five years ago and more than double federal targets. According to the CDC, infection from this bacteria is usually caused by eating raw or undercooked chicken, and it can make people sick with diarrhea.

Salmonella infections have not increased in recent years, but the bacteria still caused about 14 illnesses per 100,000 people in the United States in 2023.

Listeria caused about 0.3 illnesses per 100,000 people in the U.S. in 2023, according to data from the CDC, but it has led to several large, fatal outbreaks this year.

Boar's Head issued a recall for more than 7.2 million pounds of ready-to-eat liverwurst and some other deli meat products in late July, amid reports of dozens of hospitalizations and at least 10 deaths and a recall of nearly 12 million pounds. Ready-to-eat meat and poultry items manufactured by Brucepack have impacted schools, retailers and restaurants nationwide.

CNN's Nadia Kounang, Karma Hasan, Brenda Goodman and Meg Tirrell contributed to this report.