The outbreak hit California dairy farms in the late summer, and shortly thereafter, some dairy workers handling the raw milk began to fall ill with avian influenza themselves. Today in the state, more than 400 dairy farms are suffering outbreaks of avian influenza.

Last Sunday, Fresno-based Raw Farm voluntarily recalled a first batch of cream top whole raw milk with a "best by" date of November 27. By Wednesday, the California Department of Public Health announced that a second batch of Raw Farm cream top, with a "best by" date of December 7 had also tested positive for bird flu, based on retail sampling.

California health officials are warning not to drink another lot of raw milk from Fresno-based Raw Farm after it tested positive for bird flu virus. More testing of Raw Farm products is underway, the state said.