CHICAGO - The US Department of Agriculture said on April 29 it is collecting samples of ground beef in states with outbreaks of bird flu in dairy cows for testing but remains confident the meat supply is safe.

The USDA will analyse the ground beef to determine "whether any viral particles are present," according to a statement.

The US Food and Drug Administration said on April 26 that tests of milk showed pasteurisation killed the bird flu virus, as Colorado became the ninth US state to report an infected dairy herd.

There are no known cases of bird flu in beef cattle so far.

The USDA is collecting muscle samples at slaughter facilities of dairy cattle that have been condemned to determine the presence of viral particles. It will also use "a virus surrogate" in ground beef and cook it at different temperatures to determine how the virus is affected, the statement said. REUTERS