U.S. negotiators will be back in Tokyo soon to try and broker a deal that would ease Japan's insistence on 100 percent testing of cattle for Mad Cow disease. Japan has blocked imports of U.S. beef since a single case of Mad Cow was found in the States last December. Japan says 100 percent testing is needed to prevent contaminated beef from entering the human food chain. The U.S. says such blanket testing is unnecessary.