Over the weekend, California state health officials warned the public to avoid drinking raw milk from a Fresno-based dairy farm that was being sold in stores. H5N1, the virus driving the current bird flu outbreak, was detected in a retail milk sample.

Bird flu virus has been found in a batch of raw milk sold in California, and consumers should not drink it, the state Department of Public Health warned Sunday.

Bay Area grocery stores are pulling some raw milk off their shelves after traces of the bird flu virus were found last week in a batch of unpasteurized milk out of Fresno County. Here's what to know.