Agriculture Department scientists are conducting three beef safety studies following the first-ever discovery of bird flu in dairy cows a month ago, said a USDA spokesperson on Monday. The studies include tests of ground beef purchased at grocery stores in states with infected herds.
“USDA is confident the meat supply is safe,” said the spokesperson, because livestock is inspected for disease before slaughter. “While we have multiple safeguards in place to protect consumers, we recommend that consumers properly handle raw meats and cook to a safe internal temperature. Cooking to a safe temperature kills bacteria and viruses in meat.”
To date, 34 infected herds have been identified in nine states from Idaho to North Carolina; 12 of them in Texas. A new USDA rule came into effect on Monday that requires dairy farmers to test lactating cows before they are shipped across state lines. Researchers say they have seen transmission of the H5N1 avian influenza from cow to cow, from cows to poultry, and from herd to herd.
Researchers at Iowa State University said that up to half of the cats on dairy farms in Kansas and Texas died shortly after they were fed raw milk and colostrum from infected cows, reported CIDRAP at the University of Minnesota. While the cats could have become ill after eating infected birds, consumption of colostrum, which carries a high viral load, was a possible source of exposure, said the ISU team.
“Therefore, our findings suggest cross-species mammal-to-mammal transmission of HPAI (highly pathogenic avian influenza) H5N1 virus and raise new concerns regarding the potential for virus spread within mammal populations,” they said in the CDC journal Emerging Infectious Diseases. “The recurring nature of global HPAI H5N1 virus outbreaks and detection of spillover events in a broad host range is concerning and suggests increasing virus adaptation in mammals.”
Along with testing ground beef purchased at grocery stores in states with infected herds, the USDA also is testing samples of muscles from dairy cows that were barred at slaughter houses from entering the meat supply. The samples will be analyzed, through polymerase chain reaction (PCR) tests, for presence of viral particles. If any are found, further tests will determine in virus particles are alive.
In the third of the safety studies, the Agricultural Research Service will cook beef containing a virus surrogate at various temperatures to determine when decontamination is achieved.
“Results of these studies are forthcoming and we will share information as it becomes available,” said the USDA spokesperson.
Texas is the No. 1 cattle state with 12 million head, roughly one of every seven head in the nation, according to USDA’s Cattle inventory report. Nebraska was second with 6.25 million head, and Kansas was third with 6.15 million head. Testing has found four infected dairy herds in Kansas. No cases were reported in Nebraska.
Over the weekend, the FDA said that high-precision testing “did not detect any live, infectious virus” in pasteurized milk that carried fragments of the N5N1 virus.