Raw milk could carry flu viruses, study reveals

A study conducted by researchers at Stanford University, California, has indicated that raw milk, i.e. unpasteurised milk, may also be a source of influenza. The findings of the study, published in the scientific journal Environmental Science & Technology Letters, demonstrated that the avian influenza virus is capable of retaining its infectious load in refrigerated raw milk, thereby corroborating the recent detection of the bird flu virus in unpasteurised milk produced by a prominent Californian company. The lead study co-author, Mengyang Zhang, stated that the influenza A virus, designated H1N1 PR8, demonstrated the capacity to survive and remain infectious in milk for up to five days, raising concerns about potential transmission routes. Furthermore, the researchers discovered that avian influenza virus RNA remained detectable in raw milk for at least 57 days. Pasteurisation was found to have a significant impact on the infectious potential of the milk, with the infectious viral RNA reduced by almost 90%. Although the process did not result in the complete elimination of RNA, stressed Alessandro Zulli, another co-author of the study, exposure to influenza virus RNA does not pose a health risk to animals or humans.