The USDA is set to begin testing bulk raw milk for bird flu contamination in an effort to control the rapid spread of the virus. 

In addition to more than 100 million chickens having been infected, more than 400 dairy herds have also become infected with the virus, with more than 200 herds impacted in California alone. The virus was first detected in dairy cows in March this year.

“In partnership with state veterinarians, USDA will implement a tiered strategy to collect milk samples to better assess where H5N1 is present, with the goal to better inform biosecurity and containment measures, as well as to inform state-led efforts to reduce risk to farm workers who may be in contact with animals infected with H5N1,” according to a USDA announcement.

“Data collected over the past seven months has shown that H5N1 can be transmitted on equipment, people, or other items that move from farm to farm, including between dairies and poultry facilities.”

In other news about the highly contagious H5N1 virus, the first pig ever to be infected has been reported in Oregon, raising concerns about potential human transmission due to mutation risks. USDA's National Veterinary Services Laboratories (NVSL) has conducted genomic sequencing of virus from the poultry infected on the farm where the pig tested positive, and that sequencing has not identified any changes to the H5N1 virus that would suggest to USDA and CDC that it is more transmissible to humans.

According to the American Journal of Managed Care, industry has pushed for enhanced surveillance, which is part of what prompted the USDA to implement bulk raw milk testing. Bulk milk testing in Colorado has successfully reduced new bird flu cases in dairy cows.

The USDA’s Animal and Plant Health Inspection Service announced a tiered strategy to collect milk samples to better assess where H5N1 is present to proactively support effective biosecurity measures and to help state minimize the risk to farm workers. As of Oct. 25, the CDC was reporting that 35 people have become infected.

As for the risk to consumers, the CDC and USDA report that the virus is inactivated by pasteurization of milk. Raw, unpasteurized milk is still a concern and health officials warn consumers to not consume it because of potential contamination with H5N1 as well as E. Coli, Salmonella and other foodborne pathogens.