Uncooked milk might carry hidden dangers of flu transmission

Uncooked milk, hailed by some as a pure and nutritious various to pasteurized dairy, might include hidden risks, in response to a brand new Stanford College examine. The analysis, revealed December 12 in Environmental Science & Expertise 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 chook flu in dairy cattle have raised considerations concerning the potential for a brand new pandemic.

“This work highlights the potential threat of avian influenza transmission by 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 College of Sustainability and the Stanford College of Engineering. 

Greater than 14 million People eat uncooked milk yearly. Not like pasteurized milk, uncooked milk just isn’t heated to kill doubtlessly dangerous pathogens. Proponents of uncooked milk declare that it leaves extra helpful vitamins, enzymes, and probiotics than in pasteurized milk, and might increase 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 ladies, and folks with weakened immune programs.

The Science Behind the Danger

The researchers explored the persistence of a pressure of human influenza virus in uncooked cow’s milk at typical refrigeration temperatures. The flu virus, known 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 considerations about potential transmission pathways,” mentioned examine co-lead creator Mengyang Zhang, a postdoctoral scholar in civil and environmental engineering. “The virus may contaminate surfaces and different environmental supplies inside dairy services, posing dangers to animals and people.”

Moreover, the researchers discovered that flu virus RNA – molecules that carry genetic info however will not be thought-about a well being threat – remained detectable within the uncooked milk for at the least 57 days. By comparability, pasteurization utterly destroyed infectious influenza within the milk and decreased the quantity of viral RNA by nearly 90%, however did not remove the RNA totally. Though publicity to influenza virus RNA doesn’t pose a well being threat, 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, significantly as a result of lots 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 challenge – funded by the Stanford Woods Institute for the Surroundings’s Environmental Enterprise Tasks program – centered on human norovirus and the subfamily of viruses accountable for the COVID-19 pandemic.

Why it issues now

Within the U.S. alone, flu viruses infect greater than 40 million folks and kill greater than 50,000 yearly. Some of these 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 chook flu has not confirmed as harmful to folks but, it may mutate to change into so. Current detection of chook flu in cattle has raised questions on its potential transmission by milk and different dairy merchandise. 

The examine’s findings underscore the significance of enhancing monitoring programs, significantly as chook 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 the usage of wastewater for detection of avian influenza. That evaluation revealed business and industrial dairy waste as major sources. By analyzing wastewater, public well being officers may detect virus exercise in close by cattle populations.

“We by no means thought that wastewater might 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 the USA and the world.”

Acknowledgments

Boehm can be professor of Oceans within the Stanford Doerr College of Sustainability and a senior fellow on the Stanford Woods Institute for the Surroundings.

The examine’s coauthors additionally embrace Catherine Blish, the George E. and Lucy Becker Professor in Medication on the Stanford College of Medication; and Sehee Jong, a analysis assistant in civil and environmental engineering.

The examine was funded by the Stanford Woods Institute for the Surroundings and by the Sergey Brin Household Basis.