A senior official from the US Food and Drug Administration (FDA) said today that its nationwide survey of retail milk has found remnants of H5N1 avian flu viruses in one in five samples, with the highest concentrations in regions where outbreaks in dairy cattle have been reported.

Donald Prater, DVM, acting director of the FDA Center for Food Safety and Applied Nutrition (CFSAN), shared the new findings with state health officials who took part in a scientific symposium on H5N1 hosted by the Association of State and Territorial Health Officials (ASTHO). The results come in the wake of earlier findings this week from more limited FDA sampling, along with similar findings from a smaller set of samples tested by a lab that's part of the National Institute of Allergy and Infectious Diseases Centers of Excellence for Influenza Research and Response (CEIRR) Network.