April 26 (Reuters) - About one in five samples of commercial milk in the U.S. tested positive for traces of bird flu in a national survey, with a greater proportion coming from areas with infected herds, the U.S. Food and Drug Administration said.

There is no evidence that the milk poses a danger or that a live virus is present, regulator have said.

The FDA said late Thursday that additional testing is required to determine whether the intact pathogen is still present and if it remains infectious.

(Reporting by Leroy Leo in Bengaluru; Editing by Tasim Zahid)