The Food and Drug Administration announced Tuesday that genetic fragments of the highly pathogenic avian influenza virus H5N1 have been detected in pasteurized commercial milk. However, the tests completed so far using quantitative polymerase chain reaction (qPCR) only detect the presence of viral genetic material, but only determine whether that genetic material originates from live infectious virus particles. We can’t tell if it’s just the remains of dead virus particles killed by the pasteurization process. .
Testing is currently underway to see if viable infectious H5N1 can be identified in milk samples.
So far, the FDA still believes the milk supply is safe. “To date, we have not seen anything that would change our assessment that the commercial milk supply is safe,” the agency said. Long description of discovery and ongoing testing.
Recently, the H5N1 virus has been infecting dairy cows in the United States at an alarming rate, with the first case confirmed in a herd in Texas on March 25th. Since then, H5N1 infections have been widespread. At least 32 herds in eight states It is known that he is currently infected. The unexpected spread of infection to cattle has raised concerns that the virus is evolving to infect mammals more efficiently, increasing the risk of transmission to and between humans. It’s increasing.
But amid an alarming outbreak among the nation’s dairy herds, federal agencies appear confident that the virus poses little or no risk to the safety of the milk supply. is.
“Currently, products are pasteurized before being placed on the market, and there are concerns that this situation may pose a risk to consumer health or impact the safety of interstate commercial milk supplies.” continues to be unavailable,” the FDA said in an FAQ published Friday. . “Pasteurization continues to be proven to inactivate bacteria and viruses such as influenza in milk.”
In Tuesday’s announcement, the FDA also highlighted that multiple studies have shown that egg pasteurization processes, which use temperatures lower than those used for milk, are effective at inactivating H5N1. .
Nevertheless, the FDA, along with the Centers for Disease Control and Prevention and the U.S. Department of Agriculture, has continued to investigate potential risks, including establishing whether pasteurization can inactivate this particular virus. . The FDA noted in Tuesday’s announcement that while pasteurization is expected to kill the virus, pasteurization is “not the same as complete sterilization.”
Therefore, since the virus has been detected in raw milk, we conducted a qPCR test with the expectation that some kind of gene fragment might be found in pasteurized milk. “Based on the available information, pasteurization is likely to inactivate the virus, but this process is not expected to eliminate the presence of viral particles,” the FDA explained. “Thus, some of the samples collected indicate the presence of HPAI. [Highly Pathogenic Avian Influenza] It uses a quantitative polymerase chain reaction (qPCR) test. ”
The FDA did not say how many samples were tested, where they came from or the level of viral genetic material they contained.
The agency is currently working to assess whether it is possible to determine whether a virus particle is infectious using the egg inoculation test, which is considered the gold standard for determining virus viability. It added that results from these and other tests would be made public “in the coming days and weeks.”
”[W]We take this situation and the safety of our milk supply very seriously. “We recognize the importance of making more actionable information publicly available,” the FDA said.
Meanwhile, the agency said the CDC’s Food Safety Group is examining emergency department data and influenza testing data for unusual trends in influenza-like illness, influenza, and conjunctivitis that could indicate the spread of H5N1 infection in the population. reported that it is being closely monitored. “To date, our surveillance systems have not shown any unusual trends or activity,” the FDA said.
