Federal and state health officials are investigating a multistate E. coli outbreak linked to raw milk cheese produced by Sierra Nevada Graziers, the latest in a series of raw dairy outbreaks that have unfolded across the United States over the past two years. Three of the thirteen people sickened have developed hemolytic uremic syndrome (HUS), a kidney complication that public health officials describe as one of the most serious consequences of foodborne bacterial infection.
The U.S. Food & Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) reported on September 25, 2026, that 13 people across nine states had been infected with the outbreak strain, with eight hospitalizations and three cases of hemolytic uremic syndrome. No deaths had been reported as of that update. All nine people interviewed by public health officials reported consuming Sierra Nevada Graziers grass-fed raw milk cheese, sold in medium cheddar, sharp cheddar, jalapeno jack, and Monterey jack varieties under 8-ounce, 16-ounce, and 5-pound formats. The company initiated a recall on September 24 after the FDA contacted the firm about the outbreak. The product was distributed nationwide and online, and the FDA advised consumers to discard any recalled cheese, including product that had been frozen without its original packaging.
A Pattern, Not an Isolated Event
The Sierra Nevada Graziers outbreak is the most recent entry in a documented series of raw dairy contamination events that have sickened hundreds of Americans since late 2023. The common thread across these outbreaks is the absence of pasteurization, a heat treatment that public health authorities have identified for decades as the single most effective measure for eliminating bacterial pathogens from milk.
In March 2026, the FDA’s Coordinated Outbreak Response and Evaluation network confirmed that raw cheddar cheese and raw milk from Raw Farm, LLC, of Fresno, California, were the outbreak vehicle for a E. coli O157:H7 cluster that ultimately involved nine cases across California, Florida, and Texas. The illnesses occurred between September 2025 and February 2026, and more than half of those infected were children under five years old. Three patients were hospitalized, and one developed hemolytic uremic syndrome. Raw Farm initially disputed responsibility for the outbreak before voluntarily recalling approximately 1.5 million units of product on April 2, 2026. The same farm had been identified as the likely source of a similar E. coli outbreak in 2024, and the FDA issued Form 483 inspection observations citing inadequate equipment maintenance, insufficient preventive controls, and unsanitary handling during processing.
Separately, the Idaho Department of Health and Welfare reported in June 2026 that nearly 60 people had fallen ill after consuming raw milk from two separate milking operations, one in northern Idaho and one in southern Idaho. At least 45 of those individuals tested positive for campylobacteriosis, a bacterial infection that typically presents with diarrhea, fever, and stomach cramps. The Idaho investigation remained active as of the department’s June statement, and both milking operations were cooperating with health officials.
In Washington State, the Department of Health determined in July 2026 that raw milk from Dungeness Valley Creamery in Sequim was the most likely source of a Shiga toxin-producing E. coli outbreak that infected four people between late May and early June. No recall was issued and no news release was distributed; the state’s routine milk sample, collected June 16, nineteen days after the last known purchase by an ill person, tested negative for the pathogen. Raw milk has a shelf life of days, not weeks, meaning the batch that infected those individuals was no longer available for testing by the time the sample was collected. Earlier, in October 2025, public health officials in Oregon and Washington investigated an E. coli O103 outbreak linked to Twin Sisters raw milk cheeses, which had been aged at least 60 days in accordance with regulatory requirements for raw cheese.
The largest raw dairy outbreak in recent years occurred between September 2023 and March 2024, when a Salmonella Typhimurium outbreak linked to commercially distributed raw milk from a California dairy farm infected 171 people across five states. Seventy percent of cases and 82% of hospitalizations were among children and adolescents under 18. Four of 40 environmental samples, including raw milk and raw milk cheese aged for 60 days, tested positive for the outbreak strain.
The Pathogen Problem
Raw milk can carry a range of bacterial and viral pathogens that pasteurization is designed to eliminate. The organisms most frequently implicated in raw dairy outbreaks include Campylobacter, Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes, according to the Michigan State University review of 239 milk- and cheese-associated outbreaks reported to the CDC between 2000 and 2020. Campylobacter accounted for roughly three-quarters of estimated milk-related cases and about 71% of total economic costs associated with milk outbreaks in that analysis. Listeria, while responsible for fewer cases, carried the highest cost per illness because infections are much more likely to result in hospitalization or death.
A newer concern involves highly pathogenic avian influenza H5N1. Dairy cattle infected with the virus shed it in their milk, and most infected cows produce milk with high infectious viral loads. Consumption of that milk has produced fatal systemic infection in cats and mice, and pasteurization has been demonstrated to inactivate H5N1 in milk. The FDA has stated that all raw milk produced from herds with H5N1 infections has the potential to contain infectious virus because it is not subject to pasteurization. In December 2024, all raw whole milk and cream products on store shelves made by Raw Farm LLC were voluntarily recalled following several detections of avian flu virus in the company’s milk and dairy supply.
Hemolytic Uremic Syndrome: The Most Serious Consequence
Hemolytic uremic syndrome, or HUS, is a condition that develops in some people infected with Shiga toxin-producing bacteria, most commonly E. coli O157:H7 and increasingly E. coli O26. The syndrome is characterized by a triad of features: the destruction of red blood cells, a drop in platelet count, and acute kidney injury. The Shiga toxin damages the lining of small blood vessels, particularly in the kidneys, brain, and other organs. As red blood cells pass through damaged vessels, they break apart, and platelets clump together, forming clots that further obstruct blood flow and impair kidney function.
The kidneys are the organs most severely affected. When the toxin damages the small blood vessels that filter waste from the blood, the kidneys cannot properly clean the blood or produce normal amounts of urine. Fluid and chemical wastes accumulate in the body, causing high blood pressure, swelling, difficulty breathing, and dangerous elevations in potassium that can disrupt heart rhythm. In severe cases, patients require dialysis to perform the kidney’s filtering function.
The incidence of HUS is highest among young children. The overall incidence among children under five years of age is estimated at 1.75 per 100,000, compared with 0.38 per 100,000 among children aged five to fourteen. Approximately 15% of North American children infected with Shiga toxin-producing E. coli will develop HUS, and the case fatality rate is approximately 3%. During the acute phase, approximately 50% of children with HUS require dialysis. Most children who require dialysis recover kidney function and discontinue treatment, but the long-term burden is significant. Abnormal renal function persists in approximately 10 to 30% of patients, and a small number develop life-long neurological complications ranging from hemiparesis to learning disabilities.
The outbreak strain in the Sierra Nevada Graziers investigation is E. coli O26:H11. A 2025 study of Shiga toxin-producing E. coli in England found that O26 cases had a significantly higher risk of developing HUS compared with other serogroups, with an adjusted risk ratio of 3.13. The proportion of STEC notifications that were O26 increased from 2% to 12% between 2014 and 2023, indicating that this serogroup is emerging as a public health concern. The FDA’s outbreak advisory explicitly notes that E. coli infections can lead to “a type of kidney failure called hemolytic uremic syndrome (HUS), or the development of high blood pressure, chronic kidney disease, and neurologic problems”.
The three HUS cases in the Sierra Nevada Graziers outbreak are not isolated events. In the Raw Farm outbreak earlier in 2026, one person developed HUS. In outbreaks linked to other food vehicles, HUS has been documented repeatedly. A 2026 study of pediatric HUS cases found that among children who developed the syndrome, 56% required renal replacement therapy during the acute phase, and long-term outcomes included chronic kidney disease in some patients, with four requiring kidney transplantation. Adult HUS carries a worse prognosis than pediatric cases, with 20 to 40% of adult patients developing chronic kidney disease or requiring prolonged dialysis.
Who Bears the Burden
The populations at greatest risk of severe illness from raw dairy pathogens are consistent across outbreak investigations and public health advisories: children under five, adults over 65, pregnant women, and people with compromised immune systems. A pediatrician at UVA Health, Joshua Jakum, MD, has stated that “raw milk does not resolve lactose intolerance, treat asthma, or improve allergies”, and that it offers no nutritional superiority over pasteurized milk. He noted that toxoplasmosis and listeriosis infections during pregnancy can cause stillbirth, preterm delivery, and neonatal infections, and that E. coli O157 is associated with kidney failure in young children.
The epidemiological data reflect this vulnerability. In the 2023–2024 Salmonella outbreak linked to raw milk, 67 cases occurred in children under five, 40 in children aged five to twelve, and 13 in adolescents aged thirteen to seventeen. A separate 2025 outbreak linked to raw milk from a Florida farm sickened 21 people, including six children under ten and seven hospitalizations. A 2025 analysis published in Pediatrics found that among 171 cases in a multistate Salmonella outbreak, 70% were under 18 and children accounted for the majority of hospitalizations.
A 2026 peer-reviewed study by researchers Patricia Hsu and Felicia Wu of Michigan State University, published in Trends in Food Science & Technology, estimated that dairy-borne illness cost the United States more than $4.13 billion between 2000 and 2020. Raw milk was associated with 91.5% of milk-related hospitalizations and more than half of all milk-related illnesses in the analysis. After adjusting for population, states permitting retail raw milk sales experienced approximately four times the dairy-borne outbreak rate of states that prohibit retail sales. Raw dairy consumers faced approximately 29 times greater risk of illness, 75 times greater risk of hospitalization, and 14 times greater risk of death from the bacterial pathogens analyzed compared with people who did not consume raw dairy products.
The Science of Pasteurization
Pasteurization involves heating milk to at least 72 degrees Celsius for 15 seconds, or to 63 degrees Celsius for 30 minutes. This heat treatment reduces pathogenic bacteria to an acceptable safe level and reduces spoilage organisms, extending shelf life and improving public health. The scientific literature indicates that pasteurization has few adverse effects on the nutritional quality of milk and does not significantly alter its nutritional properties. A 2024 study on Listeria monocytogenes thermal resistance found that the organism would not survive the pasteurization process at 71.7 degrees Celsius, with a D-value of 0.9 seconds at that temperature.
Pasteurization does produce minor changes in vitamin content: it increases vitamin A while decreasing vitamins C and B2. Most physicians and dietitians consider this an acceptable trade-off, particularly because without dairy many people would not obtain sufficient vitamin A in their diets, and pasteurized milk retains adequate B2 content. Most pasteurizing farms also fortify their milk with vitamin D. UVA Health’s Jakum summarized the position of the clinical community: “Raw milk does not offer any nutritional superiority,” and pasteurization does not eliminate vitamins or fat content, it kills the organisms that cause illness.
A Legislative Countercurrent
Despite the outbreak record, state legislatures have moved in the opposite direction. More than 40 bills were introduced across at least 18 states in 2026 to expand access to raw milk and raw milk products, according to the National Conference of State Legislatures. Federal law prohibits the interstate sale of raw milk, but states retain authority over intrastate access. Raw milk is legal in some form in 43 states, with eight states permitting unrestricted retail sales: California, Maine, New Hampshire, New Mexico, Pennsylvania, South Carolina, Utah, and Washington. An additional 29 states allow some form of on-farm sales, while others permit herd-share arrangements in which consumers purchase ownership stakes in dairy animals. Only three states ban the sale of raw milk for pet consumption.
The CDC has reported rising outbreaks of bacterial illnesses associated with raw milk as access increases. The agency’s data indicate that between 2009 and 2021, a total of 143 enteric disease outbreaks confirmed or suspected to be associated with raw milk consumption were reported to the CDC. A broader review counted more than 200 outbreaks tied to raw milk that sickened more than 2,600 people and sent 225 to hospitals between 1998 and 2018.
A Question of Risk Allocation
The September 2026 Sierra Nevada Graziers outbreak adds to a body of evidence that has accumulated over decades without producing a consensus on policy. The FDA’s investigation remains ongoing, and the agency has advised consumers to monitor for symptoms including severe stomach cramps, diarrhea, fever, nausea, and vomiting, which can appear up to nine days after consumption. For the three individuals who developed hemolytic uremic syndrome in this outbreak, the consequences will extend well beyond the acute phase of illness. The long-term renal and neurological sequelae documented in HUS survivors, persistent proteinuria, hypertension, reduced glomerular filtration rate, and in some cases chronic kidney disease requiring transplantation, represent a burden that persists long after the outbreak investigation is closed.
The economic analysis published in 2026 quantified what the outbreak record has long suggested: raw dairy products impose a disproportionate share of severe illness and hospitalization relative to their share of consumption, and the populations most likely to be affected are those least able to absorb the cost. Whether state legislatures will weigh that evidence against the demand for expanded access is a decision that will be made in the 2027 legislative sessions and beyond, not in the laboratory or the hospital.
