Bird Flu: Why FDA Says Milk Safe Despite 1 in 5 Positive Tests for Virus

The Food and Drug Administration (FDA) said last week that 1 in 5 retail milk samples across the U.S. showed genetic traces of bird flu virus. So why isn't it more concerned?

Highly pathogenic avian influenza is an infectious viral illness that spreads primarily among wild and domestic birds, but the virus that causes bird flu can sometimes jump into animals, including dairy cows and, in some cases, humans.

A "multistate outbreak" of the virus has emerged among dairy cattle since mid-March, according to the U.S. Centers for Disease Control and Prevention (CDC), and two cases have been confirmed in humans. But if 1 in 5 commercial milk samples is testing positive for the virus, why have we not heard any warning regarding its safety?

The method used to test the milk samples involved analyzing them for traces of genetic material that can be found in the circulating strain of the bird flu virus. But just because there are traces of its DNA doesn't mean the milk contains active forms of the virus itself.

Following these initial findings, the FDA conducted further analysis to determine whether any infectious virus was present in the samples. "This additional testing did not detect any live, infectious virus," the agency said in a statement on April 26. "These results reaffirm our assessment that the commercial milk supply is safe."

The FDA will continue to test positive milk samples as part of an ongoing study in coordination with the U.S. Department of Agriculture. However, its results so far have confirmed that "pasteurization is effective against this virus."

Pasteurization involves heating milk to a specific temperature to kill off any harmful bacteria or viruses it might contain. "Even if virus is detected in raw milk, pasteurization is generally expected to eliminate pathogens to a level that does not pose a risk to consumer health," the FDA said.

"Based on available information, pasteurization is likely to inactivate the virus," the agency said. "However, the process is not expected to remove the presence of viral particles."

The CDC will continue to monitor bird flu in people with animal exposure, but for now it is confident that "the current public health risk is low."

However, it still recommends the following actions to keep yourself safe from bird flu:

• Avoid direct contact with wild birds
• Report sick or dead birds to your local authority
• Avoid unprotected direct physical contact or close exposure to cattle

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