Unpasteurized milk will now be tested in effort to tackle H5N1 in dairy cattle

Photo: VanderWolf Images/Adobe Stock

A new federal order issued by the US Department of Agriculture (USDA) is mandating that raw, or unpasteurized, milk samples nationwide now be collected and shared with the agency for testing. The new order adds to the USDA’s National Milk Testing Strategy (NMTS), which expands on efforts by the USDA and federal and state partners since the detection of highly pathogenic avian influenza (HPAI) H5N1 in dairy cattle in March 2024.

Per the USDA announcement, as part of the new federal order, it will now be required that¹:

1. Raw milk samples be shared, upon request, from any entity responsible for a dairy farm, bulk milk transporter, bulk milk transfer station, or dairy processing facility that sends or holds milk intended for pasteurization.
2. Herd owners with positive cattle provide epidemiological information that enables activities like contact tracing and disease surveillance.
3. Private laboratories and state veterinarians report positive results to the USDA that come from tests done on raw milk samples drawn as part of the NMTS.

Mandatory testing of lactating cows before interstate shipment will still be required. Additionally, privately owned laboratories and state veterinarians must still report positive test results linked to the corresponding tests.

“Since the first HPAI detection in livestock, USDA has collaborated with our federal, state and industry partners to swiftly and diligently identify affected herds and respond accordingly. This new milk testing strategy will build on those steps to date and will provide a roadmap for states to protect the health of their dairy herds,” said Tom Vilsack, Agriculture secretary, in a USDA release.¹

About the NMTS

According to the USDA, the NMTS was created to¹:

• increase USDA’s and public health partners’ understanding of the virus’ spread in the United States through a structured, uniform, and mandatory testing system that will help identify which states and specific herds within them are affected with H5N1
• support the rapid implementation of improved biosecurity measures to decrease the risk of transmission to other livestock
• inform critical efforts to protect farmworkers to help lower their risk of exposure

The NMTS will involve collaboration between USDA’s Animal and Plant Health Inspection Service (APHIS) and each state in the contiguous US to carry out testing that meets the specific needs of each state while aligning with the strategy’s standards. Once a state begins testing, APHIS will place it into 1 of 5 stages based on HPAI H5N1 prevalence:

• Stage 1 (Standing Up Mandatory USDA National Plant Silo Monitoring): involves testing milk silos at dairy processing facilities
• Stage 2 (Determining a State’s H5N1 Dairy Cattle Status): the USDA will “stand up” bulk tank sampling programs to detect herds within the state that are infected with the virus
• Stage 3 (Detecting and Responding to the Virus in Affected States): focuses on detecting cases of H5N1 and effecting rapid response measures like enhanced biosecurity, movement controls, and contact tracing
• Stage 4 (Demonstrating Ongoing Absence of H5 in Dairy Cattle in Unaffected States): involves regular sampling to ensure the disease has not re-emerged, with sampling frequency decreasing as long as the state remains free of the virus
• Stage 5 (Demonstrating Freedom from H5 in U.S. Dairy Cattle): Once all states pass Stage 4, periodic sampling will be conducted to confirm long-term absence of the virus in the national herd

States included in the initial rounds of testing, per the federal order comprise of both states with dairy cows affected by H5N1 and those with no reports.² The first 6 states, announced December 6, 2024, are California, Colorado, Michigan, Mississippi, Oregon, and Pennsylvania.¹

Seven additional states were added thereafter: Indiana, Maryland, Montana, New York, Ohio, Vermont, and Washington.² Eight of these states are also part of the top 15 dairy-producing states in the US, contributing to nearly half of the country’s dairy production.²

“This testing strategy is a critical part of our ongoing efforts to protect the health and safety of individuals and communities nationwide,” Xavier Becerra, Health and Human Services (HHS) secretary, said in the release.¹ “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.”

References

1. USDA announces new federal order, begins national milk testing strategy to address H5N1 in dairy herds. News release. US Department of Agriculture. December 6, 2024. Accessed January 9, 2025. https://www.usda.gov/article/usda-announces-new-federal-order-begins-national-milk-testing-strategy-address-h5n1-dairy-herds
2. USDA creates milk testing strategy to combat H5N1 in dairy cattle. American Veterinary Medical Association. December 30, 2024. Accessed January 9, 2025. https://www.avma.org/news/usda-creates-milk-testing-strategy-combat-h5n1-dairy-cattle?utm_source=delivra&utm_medium=email&utm_campaign=todays-headlines-news