The U.S. Food and Drug Administration (FDA) has outlined its research priorities for tackling Highly Pathogenic Avian Influenza (HPAI) H5N1, which was first detected in U.S. dairy cattle in March 2024 and has since spread across several states. This novel occurrence of influenza in dairy cattle has prompted the FDA to focus on protecting both human and animal health.
In collaboration with federal and state partners, the FDA is conducting a detailed scientific analysis of commercial milk safety amid the ongoing HPAI H5N1 outbreak in North American dairy cattle. Early results indicate that U.S. retail milk remains safe; however, ongoing collective activities aim to maintain the integrity of the federal-state milk safety system.
The FDA’s research agenda, developed in partnership with the USDA’s National Poultry Research Center and APHIS’ National Veterinary Services Laboratory, along with various universities, includes three main objectives:
- Understanding inactivation methods for H5N1 in dairy products.
- Ensuring the safety of retail dairy products.
- Developing One Health interventions for HPAI H5N1.
To address the first objective, the FDA is exploring pasteurization temperature thresholds and durations needed to neutralize the H5N1 virus. Efforts include:
– Testing pre-pasteurization milk samples to understand potential virus levels.
– Conducting benchtop thermal inactivation studies to estimate the time and temperature required to inactivate the virus.
– Using continuous flow pasteurization equipment to confirm effective pasteurization parameters.
– Assessing the survival of the virus in raw milk cheeses during aging.
For the second objective, the FDA is sampling and testing milk and other dairy products at retail locations. Initial tests provided insights into the survival of the H5N1 virus post-commercial processing. A second round of testing is underway, covering about 155 dairy products, including fluid milk, various cheeses, butter, and ice cream. This round includes samples from states not previously tested and additional samples from earlier survey areas to create a comprehensive national picture. Post-pasteurization testing will continue to monitor these products.
The third objective involves developing a One Health strategy to mitigate the impact of H5N1. This includes interventions to prevent, control, or eliminate the virus in animals, milk, and the environment. Strategies may involve reducing the virus’s impact, preventing its spread, and finding alternative inactivation and disposal methods for contaminated milk.
In summary, the FDA is actively researching and implementing measures to ensure the safety of dairy products and mitigate the effects of HPAI H5N1. This comprehensive approach aims to protect public health and maintain the safety of the milk supply during this unprecedented outbreak.