Research Finds Bird Flu Stays Stable On Milking Equipment For At Least An Hour

Research has found that bird flu, or H5N1 virus, stays stable on milking equipment for at least one hour.

The report came from researchers from the University of Pittsburgh School of Medicine and Emory University in Emerging Infectious Diseases.

The study underscored the heightened risk of bird flu exposure for dairy farm workers and signals the need for wider adoption of personal protective equipment, including face shields, masks and eye protection.

Lead author Dr. Valerie Le Sage said, “Dairy cows have to be milked even if they are sick, and it has not been clear for how long the virus contained in residual milk from the milking process remains stable on the equipment. It is concerning that the virus in unpasteurized milk can remain stable for hours and potentially infect farm workers or spread from animal to animal.”

Clinical symptoms of bird flu can range from mild fever and cough to shortness of breath and pneumonia and can be lethal. Since March 2024, when the bird flu virus was first detected in dairy cattle in the U.S., the virus has spread across state lines and infected at least 3 people. While, according to the U.S. Centers for Disease Control and Prevention, the current risk to the general public remains low, flu viruses can quickly adapt to spreading from person to person.

The New York State Department of Health said to date, there have been no human cases of H5N1 bird flu and no detections in cattle in New York.

To understand the potential for spread from cattle to dairy farm workers, researchers looked at the stability of infectious flu virus particles in unpasteurized milk droplets on metal and rubber components of commercial milking equipment.

In a lab environment that mimicked the humidity and temperature of outdoor milking parlors in Texas, H5N1 virus particles suspended in milk remained stable on metal and rubber for over one hour. Particles of H1N1 virus, or swine flu, which behaves similarly to H5N1 in the lab, stayed infectious for at least 3 hours on rubber and for at least 1 hour on stainless steel.