For the second time in roughly the span of a week, Santa Clara County Department of Public Health officials tested store-bought raw milk and found evidence of the virus. The sample was collected and tested on Nov. 26.

The detection of bird flu virus this week in a batch of unpasteurized milk sold in California underscores what health experts say are the known and potential risks of the products.

A Fresno County farm has issued a voluntary recall for a second batch of raw milk after bird flu was found in a sample.