The order comes as the bird flu outbreak was detected among dairy cattle in March.

“This testing strategy is a critical part of our ongoing efforts to protect the health and safety of individuals and communities nationwide,” Health and Human Services Secretary Xavier Becerra said. “Our primary responsibility at HHS is to protect public health and the safety of the food supply, and we continue to work closely with USDA and all stakeholders on continued testing for H5N1 in retail milk and dairy samples from across the country to ensure the safety of the commercial pasteurized milk supply. We will continue this work with USDA for as long and as far as necessary.”

Beginning Dec. 16, six states California, Colorado, Michigan, Mississippi, Oregon, and Pennsylvania will begin testing the supply.

Regulators are seeking to quickly identify the dairy herds infected with bird flu. As of Friday night, 718 dairy herds had been impacted in 15 states.

There are 58 confirmed human cases of blue flu in the United States, and the first case, which stemmed from dairy cows, was recorded in April this year. While it is unknown if bird flu can be transmitted between humans, scientists are concerned that the virus could evolve and lead to another pandemic.

Pasteurization will kill the H5N1 virus. However, drinking raw milk has grown in popularity, thus sparking concern and calls for testing.

Last month, California health officials made a broad recall of farm’s raw milk following the detection of bird flu in multiple batches of raw milk from a local dairy farm. However, there have been no human bird flu cases linked to the products.