U.S. researchers found no bird flu in ground beef inoculated with influenza and cooked to medium or well-done levels, the U.S. Department of Agriculture (USDA) announced on May 16.
USDA scientists took a surrogate of the highly pathogenic avian influenza A strain H5N1 and injected it into ground beef patties. They then cooked the patties to varying temperatures.
The testing identified no virus in burgers cooked to 145 degrees or 160 degrees Fahrenheit. Those temperatures represent medium and well-done burgers.
“The researchers have determined that cooking and internal temperature of 145 are sufficient to eliminate all traces of this artificially introduced virus created in the laboratory,” Eric Deeble, a deputy assistant secretary at USDA, told a briefing.
Burgers cooked 120 degrees Fahrenheit, or rare, still had detectable levels of the surrogate present but cooking burgers to 120 degrees “substantially inactivated the virus,” the agency said in a statement.
The USDA did not immediately respond when asked for clarification on what it means by substantial inactivation.
“Either it’s inactivated or not, but what does substantially mean? Still some infectious virus left? Also viral loads tested would be interesting. Inactivation may take longer if vial loads are high,” Dr. Isabella Eckerle, a professor at the Geneva Centre for Emerging Diseases, wrote on the social media platform X.
The USDA’s Food Safety and Inspection Service (FSIS) and U.S. Centers for Disease Control and Prevention (CDC) already recommend people cook ground beef to 160 degrees to make sure bacteria is killed. The U.S. Food and Drug Administration (FDA) recommends restaurants cook ground beef to 155 degrees.
The new testing, which produced results ahead of Memorial Day, was part of an effort to reassure people that ground beef in the United States is safe to consume.
“These results validate that FSIS’ recommended cooking temperatures are sufficient to kill H5N1 in meat,” the USDA said in a statement.
The USDA previously said it tested 30 samples of ground beef from retailers, and all tested negative for H5N1, also known as the bird flu. The USDA is still analyzing muscle samples taken from slaughter facilities for dairy cattle “that have been condemned for systemic pathologies.”
Bird flu has been confirmed in dairy cattle in nine states, including Michigan and Texas, this year. One person has been confirmed to have the bird flu.
The beef in the USDA burger tests primarily came from dairy cattle, which are often killed for meat as they age, Mr. Deeble said.
The FDA identified particles of H5N1 in 20 percent of milk pulled from grocery store shelves but has since said tests showed no live virus in the pasteurized samples.
Wastewater Surveillance
Dr. Nirav Shah, principal deputy director of the CDC, told reporters Thursday that the agency’s newly posted wastewater detection dashboard on influenza A, of which H5N1 bird flu is a subtype, has identified high levels of the virus in Illinois and Florida, which have not yet reported positive cases in dairy cattle.
Scientists with the Icahn School of Medicine at Mount Sinai and other institutions also reported this week finding H5N1 in wild birds in New York City through November 2023, a month before the flu is believed to have jumped to cattle.
Dr. Shah said the data in concert with the milk findings “suggest that there may be herds that are harboring H5N1 but have not yet tested positive.”
Wastewater tests cannot determine the source of the virus, which could be from humans, infected milk, or farm runoff. Scientists are closely watching for changes in the virus that could allow it to spread more easily among humans.
The CDC has not detected any increased rates of H5N1 in people, Dr. Shah said, adding that the agency is working with local officials to understand why these wastewater sites show higher-than-expected levels of influenza A.
“At the dairy farm level, thus far we’ve not seen corresponding reports, but those investigations are still underway,” Dr. Shah said.
The CDC has urged states to provide protective gear to all slaughterhouse workers, and anyone involved in the production of milk, including in states without positive herds.
He said the CDC so far has not had any individual farm workers take up the agency’s offer last week of $75 compensation to participate in studies of the outbreak. “We’re not giving up hope,” he said. “We are in constant conversation with a number of states.”
Reuters contributed to this report.
From The Epoch Times