Raw Milk E. coli O157 Outbreak California 2006: CDC
Raw Milk, Raw Colostrum, Real Consequences: CDC (2008)
The study: Centers for Disease Control and Prevention. (2008). Escherichia coli O157:H7 infections in children associated with raw milk and raw colostrum from cows — California, 2006. MMWR Morbidity and Mortality Weekly Report, 57(23), 625–628.
On September 18, 2006, the California Department of Public Health was notified of two children hospitalized with hemolytic uremic syndrome. One had culture-confirmed E. coli O157:H7; both had consumed raw cow milk in the week before illness onset. Four additional cases in children — raw milk or raw colostrum from the same dairy — were identified over the following three weeks. The CDC’s 2008 MMWR report on the investigation is the raw-milk risk documented in its starkest form: the regulated, licensed dairy, the children, the HUS.
The investigation
The epidemiological and the environmental investigation — CDPH, the California Department of Food and Agriculture, and four local health departments — traced the six cases to a single licensed raw-milk dairy (dairy A), which sold raw milk, raw cream, raw butter, raw cheese, raw colostrum, and kefir under one brand at California retail stores and nationwide online. The vehicle identification (the raw milk and the raw colostrum from dairy A), the case-finding (the HUS surveillance catching the severe cases, the interviews catching the milder), and the product tracing followed the outbreak-investigation playbook — applied to the product sold legally.
The regulatory paradox
The outbreak’s uncomfortable dimension: in California, the intrastate sale of raw milk and raw colostrum was (and is) legal and regulated. Dairy A was licensed. The regulatory framework — the licensing, the standards, the inspections — did not prevent the outbreak. The MMWR’s conclusion stated it plainly: raw milk in its several forms, including colostrum, remains a vehicle of serious enteric infections even where its sale is regulated. The regulation reduced the risk; it did not eliminate it. The outbreak became the evidence the raw-milk policy debates cite on both sides — the proponents noting the rarity, the public-health side noting the severity.
The legislative aftermath
As a result of this and other outbreaks, California enacted legislation (AB 1735), effective January 1, 2008, setting a limit of 10 coliforms per milliliter for raw milk sold to consumers — the outbreak-to-regulation pipeline operating within the legal-raw-milk framework: not the prohibition but the tightened standard. The coliform limit (the indicator, not the pathogen) reflected the regulatory compromise: the measurable standard, the enforceable number, the risk reduced if not removed.
The enduring message
The 2006 California outbreak is the raw-milk investigation the pediatricians cite: the children, the HUS, the licensed dairy, the regulated product — the case against the “safe raw milk” claim in its most documented form. The MMWR’s final recommendation was unambiguous: to reduce the risk of E. coli O157 and other infections, consumers should not drink raw milk or raw milk products. The outbreak’s six cases are few beside the produce outbreaks’ hundreds; its victims’ ages and its product’s legality give it the disproportionate weight. The regulated raw milk still carries the unregulated risk.
Source: Centers for Disease Control and Prevention. (2008). Escherichia coli O157:H7 infections in children associated with raw milk and raw colostrum from cows — California, 2006. MMWR Morbidity and Mortality Weekly Report, 57(23), 625–628.