Pasteurisation proven to halt H5N1 spread in milk – St Jude Children’s Research Hospital reports

USA – A recent study by St Jude Children’s Research Hospital has confirmed that standard pasteurisation completely inactivates the H5N1 avian influenza virus in milk, a finding that offers significant reassurance to the dairy industry and consumers alike.

Researchers tested milk contaminated with H5N1 and found no viable virus after pasteurisation, even though viral RNA fragments remained detectable. Laboratory animals exposed to the treated milk showed no infection or illness, underscoring the process’s effectiveness.

“Pasteurized milk containing H5N1 is safe; raw milk is not,” said Stacey Schultz-Cherry, a virologist at St. Jude Children’s Research Hospital in Memphis, Tenn.

The study’s conclusion is clear: properly pasteurised milk is safe, even when sourced from infected herds. However, unpasteurised or raw-milk products continue to pose health risks and should be strictly avoided.

For the dairy sector, the findings reaffirm pasteurisation as a non-negotiable safeguard in milk processing. Experts urge processors to maintain validated time-temperature controls, rigorous traceability, and transparent communication to sustain consumer confidence.

As concerns around zoonotic transmission grow, this evidence strengthens the case for continued investment in hygienic processing and robust quality systems, ensuring the dairy value chain remains resilient, safe, and science-led.

Since the first confirmed infection in the United States in dairy cows in 2024, H5N1 has spread to 17 states. That includes Nebraska for the first time, the U.S. Department of Agriculture reported September 15. The spread is concerning because the virus can spill over to humans.

The USA Centers for Disease Control and Prevention has confirmed multiple H5N1 infections in people, including one death. CDC has linked these cases to wild birds, backyard flocks and unpasteurized or raw milk.

USA food and safety regulators have said that milk pasteurized at 72° Celsius for 15 seconds is safe for human consumption. But laboratory tests have picked up fragments of viral genomic material in it, including RNA and the protein hemagglutinin, the “H” in the name, that helps H5N1 latch onto cells.

“Detecting viral RNA is like seeing a footprint or a shadow. It shows something was there, but it’s not alive or capable of moving on its own,” Schultz-Cherry said.

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