U.S. government to begin expanded testing of milk supply to better track the spread of bird flu

The USDA will require testing of milk stored before processing to better track the bird flu outbreak in dairy cattle. (madisonwi/E+/Getty Images via CNN Newsource)

The U.S. Department of Agriculture will begin testing raw milk from dairy silos around the nation in an effort to better track the H5N1 bird flu that has been spreading in dairy cattle since March.

The agency announced the expanded testing of the milk supply in a new federal order issued on Friday.

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Infectious disease experts have called for expanded testing since the beginning of the outbreak, arguing that the virus can’t be contained until farms, vets and federal regulators know where it is spreading. Dairy farmers had initially resisted calls for more widespread testing, fearing a loss of income if their herds were quarantined.

“Among many outcomes, this will give farmers and farmworkers better confidence in the safety of their animals and ability to protect themselves, and it will put us on a path to quickly controlling and stopping the virus’ spread nationwide,” Agriculture Secretary Tom Vilsack said in a news release.

The new order requires the sharing of raw milk samples, upon request, from dairy farms, bulk milk shippers, milk transfer stations or dairy processing facilities that send or hold milk for pasteurization.

It also requires that herd owners with cattle that test positive for bird flu provide information that enables contact tracing and disease surveillance.

Lastly, it requires labs and vets that have positive test results for H5N1 to report them to the USDA.

The USDA said it will immediately begin testing milk in storage silos at dairy processing facilities across the country for the H5N1 virus.

Based on those results, the agency will work with states to do bulk tank testing at farms, and If the milk is positive, officials say they will work quickly to identify “specific cases” and establish enhanced biosecurity measures.

Once all the herds in the states are cleared, the USDA will continue to monitor milk in bulk tanks to make sure the infection doesn’t re-emerge.

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The first round of testing is scheduled to begin the week of December 16, though some states have already started testing that complies with these requirements, the USDA noted.

Six states will be included in the first round of testing: California, Colorado, Michigan, Mississippi, Oregon and Pennsylvania. While California, Colorado and Michigan are known to have had infected herds, Mississippi, Oregon and Pennsylvania have not reported any problems. The milk testing in those states will help authorities better understand whether bird flu is a threat in areas where the illness has so far gone undetected.

The USDA first announced the new National Milk Testing Strategy in October. Friday’s order is the first time it has released the specific details of its plans.

The milk is being tested before pasteurization, a process that heats milk to a specific temperature over time and kills harmful bacteria and viruses. “Even if the virus is detected in raw milk, the current pasteurization process … will inactivate the virus,” the US Food and Drug Administration said. Almost all the milk sold in the United States is pasteurized.

Health officials have long warned against drinking raw milk or feeding it to animals. Raw milk is not pasteurized and can can carry disease-causing pathogens such as listeria, campylobacter, salmonella, E. coli and bird flu virus. In California, Raw Farm milk and cream was recalled and product distribution was suspended after bird flu virus was detected recently in samples from store shelves, dairy storage and bottling sites. No illnesses have been linked to the milk.