Post by Nadica (She/Her) on Jun 18, 2024 4:57:39 GMT
Bird flu virus outlasted pasteurization, study finds - Published June 17, 2024
A small but detectable amount of H5N1 bird flu survived a standard pasteurization method on milk infected with high concentrations of the virus, National Institutes of Health scientists wrote Friday in the New England Journal of Medicine.
Why it matters: While evidence continues to indicate that the commercial milk supply is safe, the more virus there is in milk, the longer it takes to kill all of it, public health officials warn.
Because the findings reflect experimental conditions in a lab, the next step involves studies that replicate real-world conditions with actual pasteurization equipment.
Catch up quick: There's limited data on how susceptible avian influenza is to pasteurization methods used by the dairy industry.
Researchers at the National Institute of Allergy and Infectious Diseases put it to the test by spiking raw, unpasteurized cow milk with virus isolated from a dead mountain lion in Montana, then heat-treated the milk at 63℃ and 72℃ for different periods of time.
The 63℃ process caused a marked decrease in infectious virus levels within two and a half minutes, "so standard bulk pasteurization of 30 minutes at 63℃ has a large safety buffer," researchers wrote.
But small amounts of virus could remain infectious in milk flash-pasteurized at 72℃ for 15 seconds, the researchers said.
To date, 95 cattle herds across 12 states have been affected with H5N1, with three human infections detected in farm workers. The virus so far has shown no ability to spread from person to person.
A small but detectable amount of H5N1 bird flu survived a standard pasteurization method on milk infected with high concentrations of the virus, National Institutes of Health scientists wrote Friday in the New England Journal of Medicine.
Why it matters: While evidence continues to indicate that the commercial milk supply is safe, the more virus there is in milk, the longer it takes to kill all of it, public health officials warn.
Because the findings reflect experimental conditions in a lab, the next step involves studies that replicate real-world conditions with actual pasteurization equipment.
Catch up quick: There's limited data on how susceptible avian influenza is to pasteurization methods used by the dairy industry.
Researchers at the National Institute of Allergy and Infectious Diseases put it to the test by spiking raw, unpasteurized cow milk with virus isolated from a dead mountain lion in Montana, then heat-treated the milk at 63℃ and 72℃ for different periods of time.
The 63℃ process caused a marked decrease in infectious virus levels within two and a half minutes, "so standard bulk pasteurization of 30 minutes at 63℃ has a large safety buffer," researchers wrote.
But small amounts of virus could remain infectious in milk flash-pasteurized at 72℃ for 15 seconds, the researchers said.
To date, 95 cattle herds across 12 states have been affected with H5N1, with three human infections detected in farm workers. The virus so far has shown no ability to spread from person to person.