A bit(e) of History of E. coli and Cheeses

E. coli Cheese 2025: Washington State Department of Health is working with local, state, Oregon Health Authority and federal public health partners to investigate Shiga Toxin-Producing E. coli (STEC) infections linked to consumption of aged, raw milk cheese. Two Washington residents and one Oregon resident have developed STEC infections caused by E. coli O103. Molecular fingerprinting of the bacteria from the three cases is extremely similar, suggesting a common source is the cause of the infections. One individual is a child (<5 years of age) and two individuals are adults. Illnesses occurred between September 5 and September 16, 2025.

The Oregon case reported consuming Twin Sisters Creamery Farmhouse cheese prior to onset of symptoms. This cheese is made from raw, unpasteurized milk. This cheese is aged at least 60 days, as required by law, to reduce potential pathogens.  An opened, leftover Twin Sisters Creamery Farmhouse cheese sample tested positive for E. coli O103 and the molecular fingerprinting of this organism is very similar to fingerprints from the case-organisms. 
A second, unopened Twin Sisters Creamery cheese collected from a retail location by the Washington State Department of Agriculture (WSDA) also tested positive for STEC. Additional unopened samples of cheese from multiple retail locations were collected for testing with results pending.

E. coli Cheese 2010: CDC is collaborating with public health officials in Arizona, California, Colorado, New Mexico, Nevada, the U.S. Department of Health and Human Services’ Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) to investigate a multistate outbreak of human infections due to E. coli O157:H7. 

Thirty-eight persons infected with the outbreak strain of E. coli O157:H7 have been reported from five states. The number of ill persons identified in each state with this strain is as follows: AZ (19), CA (3), CO (11), NM (3) and NV (2). Dates of illness onset range from October 16, 2010 through October 27, 2010. Patients range in age from 1 to 85 years, and the median age is 16 years. There have been 15 reported hospitalizations, 1 case of hemolytic uremic syndrome (HUS), and no deaths.

Laboratory testing conducted by the New Mexico Department of Health on an unopened (intact) package of Bravo Farms Dutch Style Gouda Cheese purchased from a Costco retail location identified E. coli O157:H7 matching the outbreak strain. This was the first confirmation from an unopened cheese sample and was consistent with previous laboratory testing conducted on two opened packages of the Bravo Farms Dutch Style Gouda Cheese purchased at Costco, which also identified E. coli O157:H7 matching the outbreak strain. These opened packages were from two different case patients’ homes. Testing on two additional opened packages from other case patients’ homes was in process.

On November 23, 2010, Bravo Farms expanded its recall to include all its cheeses. This action follows laboratory testing by the California Department of Food and Agriculture that reveals the presence of Listeria monocytogenes and E. coli O157:H7 in cheese samples. Bravo Farms sells a variety of cheeses at retail stores throughout the US, mainly on the West coast, including Gouda, Pepper Jack, Tulare Cannonball, and several different styles and flavors of Cheddar cheese. To date, no illnesses associated with L. monocytogenes in Bravo Farm cheese have been reported. 

E. coli Cheese 2024: CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA), collected different types of data to investigate a multistate outbreak of E. coli O157:H7 infections. Epidemiologic data showed that Raw Farm brand raw cheddar cheese made people sick in this outbreak.

A total of 11 people infected with the outbreak strain of E. coli were reported from 5 states (see map). Illnesses started on dates ranging from October 18, 2023, to February 5, 2024 (see timeline). Of 11 people with information available, 5 were hospitalized and 2 developed hemolytic uremic syndrome, a serious condition that can cause kidney failure. No deaths were reported.

The true number of sick people in this outbreak was likely much higher than the number reported, and the outbreak may not have been limited to the states with known illnesses. This is because many people recover without medical care and are not tested for E. coli.

State and local public health officials interviewed people about the foods they ate in the week before they got sick. Of the 10 people interviewed, 7 (70%) specifically reported eating Raw Farm brand raw cheddar cheese. This percentage was significantly higher than the 4.9% of respondents who reported eating any raw milk cheese in the FoodNet Population Survey—a survey that helps estimate how often people eat various foods linked to diarrheal illness. This difference suggested that people in this outbreak got sick from eating Raw Farm brand raw cheddar cheese. 

Republished with permission from Bill Marler and Marler Clark. Copyright (c) Marler Clark LLP, PS. All rights reserved.