In a recent study conducted by the US Food and Drug Administration (FDA), it has been confirmed that the commonly used flash pasteurization method effectively neutralizes the bird flu virus present in milk. The study, which involved testing 275 bulk samples of raw milk collected from farms in four states, revealed that half of the samples tested positive for traces of influenza. Furthermore, a quarter of the positive samples were found to be infectious.

The FDA's Center for Food Safety and Applied Nutrition highlighted that the milk samples tested were intended for pasteurization and not for direct sale to consumers. However, the agency expressed concern over states that permit the sale of raw milk for human or animal consumption, as it could potentially expose individuals to the virus.

Dr. Don Prater, the acting director of the FDA's Center for Food Safety and Applied Nutrition, emphasized that the FDA has long advised against consuming raw milk due to the risk of contamination. Consequently, the FDA urged states to issue stronger warnings to the public about the dangers of raw milk and to test herds producing raw milk for sale. Additionally, the agency recommended that states use their regulatory authority to halt the sale of raw milk within affected areas or states where dairy herds have tested positive for bird flu.

To assess the amount of virus present in milk reaching pasteurization plants, FDA scientists measured the concentrations of the virus in the collected samples. Subsequently, they introduced live H5N1 virus into uninfected raw milk obtained from the University of Georgia dairy and subjected it to the flash pasteurization process. The testing involved a preheating step, which previous studies had not included, and found that it fully neutralized all infectious virus present.

Dr. Prater explained that the findings shed light on earlier research that identified inert fragments of the H5N1 virus in 1 in 5 dairy products retrieved from store shelves. He stated that the study helps elucidate the commercial processing involved and confirms the safety of pasteurized milk for consumption.

As part of the ongoing assessment, the FDA is set to conduct another round of sampling, this time focusing on dairy products purchased at grocery stores, including cheese made from raw milk. However, the results of this testing have not yet been released. The FDA has made its latest study available as a preprint and has submitted it to the Journal of Food Protection for review and publication consideration.