WASHINGTON, March 11 (Xinhuanet) -- The U.S. Agriculture Department is investigating a possible new case of mad cow disease,the agency chief veterinarian said Saturday.

    John Clifford said in a statement that "last night we received an inconclusive test result on a rapid test from an animal sampled as part our enhanced BSE (bovine spongiform encephalopathy) surveillance program."

    He said that as a normal component of most screening tests, the"inconclusive" result could possibly be positive and did not mean a new case of mad cow disease found in the animal.

    The cow did not enter the human food chain or the animal feed chain, Clifford added.

    The result is undergoing further tests and will be available in four to seven days, he said.

    News of the possible new case comes as the United States tries to convince Japan, traditionally the NO. 1 market for U.S. beef, to buy its beef again.

    "I want to emphasize that human and animal health in the United States are protected by a system of interlocking safeguards and that we remain very confident in the safety of U.S. beef," Clifford said.

    There have been two confirmed cases of mad cow disease in the United States. The first was reported in December 2003.

    The Agriculture Department raised its testing level in response to the disease. As of Friday, more than 600,000 of the country's estimated 95 million heads of cattle had been tested. Enditem