Federal food safety authorities are investigating an outbreak of E. coli that sickened seven people in three states after some of them reported eating cheese made by a raw dairy farm in California, but the company denied its products caused the illnesses.
Five people in California, one person in Texas and one person in Florida became ill with E. coli infections between September 1 and February 13, the Food and Drug Administration said. Three of them told state and local public health investigators that they had eaten cheddar cheese made by Raw Farm LLC, a family farm whose founder said in an interview Wednesday that no evidence of the bacteria had been found in its products.
The FDA said epidemiological evidence indicated the farm was “the likely source of this outbreak,” adding that its investigation was looking to determine the source and whether other products were linked to the illnesses.
In an advisory posted on its website, the Centers for Disease Control and Prevention listed the affected products as blocks of raw cheddar cheese and shredded raw cheese, and said consumers should consider not eating them while the investigation is ongoing. Some stores have voluntarily removed these products from shelves, although official results have not been released, the company said.
Mark McAfee, the founder of the farm, which spans 800 acres in Fresno and has 1,200 cows, said the company disagrees with statements made by the FDA and CDC regarding their products and the outbreak.
The farm has an on-site lab and technicians, Mr. McAfee said. “We test all of our milk every day and we test the cows every week as well as all finished products,” he said.
Aaron McAfee, the farm’s president, said in an interview that farm technicians conducted 3,238 routine tests specifically for E. coli from Sept. 1 to March 6, including on barns, factories, finished products and milk.
“All of our products released to the market have a negative certificate of analysis that shows no pathogens detected,” he said.
California public health authorities have taken no action against the farm and state test results are expected Friday, Mark McAfee said. The California Department of Public Health did not immediately respond to a request for comment Wednesday.
Raw Farm said in a statement posted online this week that it tested its products and found them “negative for all harmful bacteria,” including E. coli O157-H7, referring to a strain that causes serious intestinal infections in humans.
The FDA said E. coli bacteria are genetically similar, meaning people involved in this outbreak were likely to have shared a common source of infection, but added that it, too, was not aware of any farmhouse raw Cheddar cheese products from this time period that tested positive for E. coli.
The farm has refused to recall its Cheddar cheese products, the FDA and Mark McAfee said.
Two of the people who became ill were hospitalized, the food agency said, and four of them were 3 years old or younger. No deaths or acute illnesses have been reported following the outbreak, the agency said.
Public health officials have warned for decades that consuming raw dairy products can cause foodborne illnesses, some of which can be serious or even fatal. Milder cases can cause nausea, vomiting, stomach pain, fever, headache and body aches.
Milk can harbor bacteria found in cow feces, in dirt, or on the hands of people who handle them. During pasteurization, milk is heated to kill these microbes, but in raw milk and dairy products made from it, microbes can survive and grow.
Investigators used a genetic testing method called whole genome sequencing to investigate this outbreak. According to the FDA, these tests suggest that sick patients were made ill by a common source.
It’s like finding the same “unique fingerprint” of a pathogen in every sick person, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
“Epidemiologically, this is the smoking gun, that they ever isolate it from the product,” Dr. Osterholm said. It’s common for the FDA to recommend that companies stop selling their products based on this evidence, even if they haven’t yet found the same pathogen in the product itself, he said.
Foodborne outbreaks have previously been linked to Raw Farm products, including raw cheddar linked to an outbreak of E. coli in 2024. Unpasteurized milk sold by the farm has been linked to salmonella infections in at least 171 people, 22 of whom were hospitalized from September 2023 to March 2024.
This outbreak was the largest linked to unpasteurized milk in more than two decades, according to CDC figures.
Under a previous name, Organic Pastures Dairy Company, the farm has been implicated in outbreaks of E. coli occurring in 2006, 2011 and 2016.
Aaron McAfee said in a video this week that the latest case was the first time the farm, established in 1998, had refused a voluntary recall.
“In the past, we’ve had recalls. We owned it whether we agreed with it or not,” he said in the video. “We’ve always learned something and we’re proud of it. It’s different,” he said.
