The mandate targeting bulk milk transporters and dairy processors is meant to help identify herds that have caught the virus, which has spread among livestock.

The US national milk supply will begin being tested for bird flu, according to a new federal order announced on Friday by the Department of Agriculture. As part of the mandate, entities and firms that handle raw milk - such as dairy processors - must collect samples to share with agriculture officials.

The move is aimed at creating comprehensive surveillance for the virus, which has been circulating in U.S. dairy cattle since it was detected earlier this year.