Raw Farm Dairy, located in Fresno, has recalled raw milk produced on November 9^th.  This action follows demonstration of RNA consistent with H5 influenza virus in a retail milk sample collected by the Santa Clara Health Department. This action is in accordance with the State of California surveillance program for bovine influenza-H5N1.

The operators of Raw Farm Dairy should have recognized the possibility of bovine influenza infection based on a depression in milk yield among animals within their herd and a physical change in the appearance of milk. The dairy operators should have voluntarily withheld milk until the results of an assay for the presence of virus disclosed freedom from infection. Releasing milk of questionable wholesomeness was unethical and contrary to the health-promoting principles apparently followed by producers of ‘natural’, certified organic and raw milk and related foods.

This case illustrates the risk of consuming raw milk, since the virus if present, could result in human infection even if only producing mild respiratory infection and conjunctivitis.  The ingestion of milk containing H5N1 virus by a person infected with a seasonal strain of human influenza could result in a recombinant event.  Identification of RNA derived from H5 viral influenza in this case is an indication of the need for surveillance, given that 335 cases of bovine influenza have been diagnosed in California herds over the past three months.

The virus is effectively inactivated by pasteurization but raw milk can contain a wide range of bacterial pathogens and now evidently viruses of potential zoonotic significance