Alert as bird flu found in 'raw' cow's milk - and it may be able to survive heat treatment and refrigeration, say scientists By Chris Pollard Published: 18:22, 24 May 2024 | Updated: 18:30, 24 May 2024 e-mail View comments Deadly bird flu has been found in raw cow’s milk and may be able to survive standard pasteurisation, a study suggests. Scientists tested milk samples from herd infected with H5N1 in New Mexico and found high levels of the virus, even after it had been refrigerated at 4c (39F). It means animals drinking the milk, including humans, stand a risk of catching it.
When mice were fed the untreated milk they showed signs of illness from the first day, and the virus was detected in their respiratory systems and other organs of their bodies. The researchers heat-treated the milk at 72C, similar to how supermarket milk is pasteurised, for various lengths of time. Raw milk is available at some health food stores and trendy coffee shops Bird flu has been found in UK chickens but no cases in cows have been reported In the UK, milk must be heated for at least 15 seconds, and no longer than 25 seconds.
The researchers found the virus was reduced, but not eliminated, even after 20 seconds of heating. Only after 25 seconds was it destroyed. They wrote in the New England Journal of Medicine: ‘Our data indicate that H5N1 virus in untreated milk can infect susceptible animals that consume it.
‘Heat treatment for 15 or 20 seconds reduced virus titers by more than 4.5 log u.
