Raw Milk Cheese May Not Be Enough to Kill Bird Flu Virus

A recent study by Cornell University’s scientists suggests that raw milk cheese may not be enough to kill the H5N1 avian flu virus. The US Food and Drug Administration (FDA) funded the study, which aimed to assess the threat of H5N1 from potentially contaminated raw milk cheese.

The researchers made raw-milk cheese from raw milk spiked with H5N1 under different pH levels, ranging from 6.6 to 5.0. They tested samples of raw milk cheddar cheese that was inadvertently produced with H5N1-contaminated raw milk after an outbreak in dairy cows on a farm.

The results show that the virus remained throughout the cheese-making process and for up to 60 days of aging at the 6.6- and 5.8-pH levels. However, the virus didn’t survive at the 5.0-pH level, which is the most acidic. The study’s findings raise food safety concerns not just for aged raw-milk cheese but also for other raw-milk products.

The researchers warn that ingestion of contaminated raw dairy products repeatedly may increase the probability of infections. While the infectious dose of the virus to humans is not known, the risk remains a concern.

In related news, the New York City Health Department is investigating two cats with H5 avian flu infections, and the USDA reported more H5N1 detections in poultry in Oklahoma and Philadelphia.

Source: https://www.cidrap.umn.edu/avian-influenza-bird-flu/aging-might-not-be-enough-eliminate-h5n1-viruses-raw-milk-cheese