Infectivity\nand Persistence of Influenza A Virus in\nRaw Milk

Influenza A viruses present important public health risks,\nwith\nrecent outbreaks of highly pathogenic avian influenza (HPAI) H5N1\nin dairy cattle raising concerns about potential transmission through\nraw milk consumption. This study investigated the persistence of influenza\nA virus H1N1 PR8 (IAV PR8) in raw cow milk at 4 °C. We found\na first-order decay rate constant of −2.05 day<sup>–1</sup> equivalent to a <i>T</i><sub>99</sub> of 2.3 days. Viral\nRNA remained detectable for at least 57 days with no degradation.\nPasteurization (63 °C for 30 min) reduced infectious virus to\nundetectable levels and reduced viral RNA concentrations, but reduction\nwas less than 1 log<sub>10</sub>. These findings highlight the potential\nrisk of zoonotic virus transmission through raw milk consumption and\nunderscore the importance of milk pasteurization. The prolonged persistence\nof viral RNA in both raw and pasteurized milk has implications for\nfood safety assessments and environmental monitoring, particularly\nin the context of the environmental surveillance of influenza viruses.