In January 2016, California public health officials investigated an outbreak of E. coli O157:H7 infections associated with Organic Pastures raw milk. Ten cases were identified. Four people were hospitalized. No one died. Two of the hospitalized cases developed Hemolytic Uremic Syndrome (HUS). Dates of illness onset ranged from January 14, 2016 to January 28, 2016.

On February 2016, California Department of Public Health Food and Drug Branch (FDB) investigators collected a total of 97 environmental and product samples at Organic Pastures, including 20 product samples (raw milk and cream), 56 cow feces, 18 soil, and 3 water. E. coli O157 was not detected in any of the product samples. However, multiple environmental samples tested positive for E. coli O157:H7, including feces, soil, and water. These environmental samples were determined to have 6 different PFGE patterns. There were two PFGE pattern combinations that were predominate. Sixteen of the 22 positive samples had the same 2 PFGE patterns as seen in case patients.

The outbreak was assigned CDC Cluster Code 1602CAEXH-1.