Uncooked milk, hailed by some as a pure and nutritious different to pasteurized dairy, might include hidden risks, in response to a brand new Stanford College examine. The analysis, revealed December 12 in Environmental Science & Know-how Letters reveals that influenza or flu virus can stay infectious in refrigerated uncooked milk for as much as 5 days. The findings come at a time when outbreaks of chicken flu in dairy cattle have raised issues in regards to the potential for a brand new pandemic.
“This work highlights the potential danger of avian influenza transmission via consumption of uncooked milk and the significance of milk pasteurization,” mentioned examine senior creator Alexandria Boehm, the Richard and Rhoda Goldman Professor of Environmental Research within the Stanford Doerr Faculty of Sustainability and the Stanford Faculty of Engineering.
Greater than 14 million People eat uncooked milk yearly. Not like pasteurized milk, uncooked milk just isn’t heated to kill probably dangerous pathogens. Proponents of uncooked milk declare that it leaves extra useful vitamins, enzymes, and probiotics than in pasteurized milk, and might enhance immune and gastrointestinal well being.
The Meals and Drug Administration has tied uncooked milk to over 200 outbreaks of sicknesses, and – along with the Facilities for Illness Management and Prevention – warns that germs, such E. coli and Salmonella, in uncooked milk current “critical” well being dangers, particularly for youngsters, the aged, pregnant girls, and folks with weakened immune methods.
The Science Behind the Threat
The researchers explored the persistence of a pressure of human influenza virus in uncooked cow’s milk at typical refrigeration temperatures. The flu virus, referred to as H1N1 PR8, survived and remained infectious within the milk for as much as 5 days.
“The persistence of infectious influenza virus in uncooked milk for days raises issues about potential transmission pathways,” mentioned examine co-lead creator Mengyang Zhang, a postdoctoral scholar in civil and environmental engineering. “The virus might contaminate surfaces and different environmental supplies inside dairy amenities, posing dangers to animals and people.”
Moreover, the researchers discovered that flu virus RNA – molecules that carry genetic info however should not thought of a well being danger – remained detectable within the uncooked milk for at the least 57 days. By comparability, pasteurization utterly destroyed infectious influenza within the milk and lowered the quantity of viral RNA by nearly 90%, however did not get rid of the RNA completely. Though publicity to influenza virus RNA doesn’t pose a well being danger, RNA-based testing strategies are sometimes used to conduct environmental surveillance of pathogens like influenza.
The extended persistence of viral RNA in each uncooked and pasteurized milk has implications for meals security assessments and environmental surveillance, notably as a result of most of the methods utilized in environmental surveillance detect RNA.”
Alessandro Zulli, examine co-lead creator, postdoctoral scholar in civil and environmental engineering
The analysis grew out of an earlier venture – funded by the Stanford Woods Institute for the Setting’s Environmental Enterprise Initiatives program – centered on human norovirus and the subfamily of viruses answerable for the COVID-19 pandemic.
Why it issues now
Within the U.S. alone, flu viruses infect greater than 40 million individuals and kill greater than 50,000 yearly. These kind of viruses can unfold from animals to people, as within the case of swine flu, which led to as many as 1.4 billion human infections globally in 2009-2010.
Though chicken flu has not confirmed as harmful to individuals but, it might mutate to turn into so. Current detection of chicken flu in cattle has raised questions on its potential transmission via milk and different dairy merchandise.
The examine’s findings underscore the significance of enhancing monitoring methods, notably as chicken flu continues to unfold amongst livestock, in response to the examine’s authors.
The examine enhances earlier analysis involving a number of of the identical researchers that pioneered using wastewater for detection of avian influenza. That evaluation revealed business and industrial dairy waste as main sources. By analyzing wastewater, public well being officers might detect virus exercise in close by cattle populations.
“We by no means thought that wastewater may very well be used to detect and reply to zoonotic pathogens circulating locally,” Boehm mentioned. “It has been superb to look at our work on detection in wastewater scaled throughout america and the world.”
Acknowledgments
Boehm can also be professor of Oceans within the Stanford Doerr Faculty of Sustainability and a senior fellow on the Stanford Woods Institute for the Setting.
The examine’s coauthors additionally embrace Catherine Blish, the George E. and Lucy Becker Professor in Drugs on the Stanford Faculty of Drugs; and Sehee Jong, a analysis assistant in civil and environmental engineering.
The examine was funded by the Stanford Woods Institute for the Setting and by the Sergey Brin Household Basis.
Supply:
Journal reference:
Zulli, A., et al. (2024). Infectivity and Persistence of Influenza A Virus in Uncooked Milk. Environmental Science & Know-how Letters. doi.org/10.1021/acs.estlett.4c00971.