The Food and Drug Administration (FDA) has increased testing of domestic milk supplies following the spread of a bird flu epidemic through avian and cattle livestock across the country. Some of the testing samples found inactive remnants of the bird flu virus, killed during the pasteurization process, the agency said. The FDA emphasized that the virus in this form is not a threat to humans and that the commercial milk supply remains safe. The agency is conducting extensive testing of egg and milk production to ensure their safety from the virus, with results from ongoing safety studies to be released in the coming days. As of Tuesday evening, the virus — known as Type A H5N1 — has been found in dairy cows in Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, Texas, and South Dakota. Only two people in the U.S. have ever been infected with the virus, including a Texas dairy worker earlier this month who recovered from minor symptoms. The FDA reiterated warnings against consuming raw or undercooked poultry and eggs, noting that the pasteurization and heat-treating process of store-purchased products ensures their safety.