is just one step. The real test is still to come, of Japan's ability to check (that) the U.S. is implementing precautions" against BSE, said Yasuhiro Yoshikawa, who heads the prion research group under the commission that drafted Thursday's report.

"The report was based on a number of preconditions, such as safety measures to be implemented in the U.S. in the future," said Yoshikawa, also professor of agricultural life science at Tokyo University. "There were moments when members (of the panel) talked about refusing to complete the report."

In the future, he said the team will not conduct risk analysis for scenarios in which over 50 percent of the preconditions are hypothetical.

A team of specialists will leave for the U.S. this week to verify that U.S. meat packing plants are using proper procedures to keep tainted meat out of exports, an agriculture ministry official said.