Financial Services, April 24 (Editor: Zhou Ziyi) The US Food and Drug Administration (FDA) said on Tuesday (April 24) that the agency found that some pasteurized milk samples contained avian influenza virus residues.

However, the agency later stressed that these samples were inactivated, which meant that the results of the study “do not represent an actual virus that may pose a risk to consumers.” FDA officials added that they are continuing to study the issue.

The FDA also wrote in a statement, “To date, there have been no findings that could change our assessment of the safety of commercial milk supply.” In other words, because commercial milk is pasteurized (milk is heated to a specific temperature to kill harmful bacteria and viruses), milk is still safe for human consumption.

Currently, FDA officials have not stated how many samples they have tested or where they have obtained them.

Lee-Ann Jaykus, an honorary food microbiologist and virologist at North Carolina State University, said the lab tests they use can detect the virus's genetic material even if the live virus is killed by pasteurization or heat treatment.

Jaykus notes, “So far, there is no evidence that this is a contagious virus, and the FDA is following up.”

Potential concerns

In fact, as early as almost a month ago, this bird flu virus was discovered in dairy cows in at least eight states in the US. The US Department of Agriculture also indicated that nearly 33 livestock herds have been affected so far.

At the beginning of this month, the US Texas state government and the Centers for Disease Control and Prevention (CDC) also announced a case of human infection with H5N1 avian influenza. A person in Texas who came into contact with dairy cows was infected with bird flu. The patient's only symptom was eye inflammation, then tested positive for the flu.

The CDC later warned that close contact or long-term unprotected contact with infected birds or other animals (including livestock) increases the risk of contracting avian influenza.

As a virus that causes diseases in millions of birds, the H5N1 avian influenza virus has been around for more than 20 years, yet there are few human infections. However, the spread seems to have expanded from birds to other groups: at the beginning of March this year, goats on a farm in Minnesota were diagnosed with the virus, the first case in US livestock; now it has been discovered that the virus can spread directly among cattle.

In response, Gregory Gray, an epidemiologist at the University of Texas Medical School, said earlier that the newly discovered cases in dairy cows in several states were a “worrying” development, as it could indicate that this strain of avian influenza no longer needs to be transmitted through birds, but directly among cattle. And the virus has mutated and may even infect humans.