Half of the 12-member group of experts tasked with assessing the safety of U.S. beef have apparently resigned, because the government announced their replacements Monday.

The six who resigned, including Tokyo Medical University professor Kiyotoshi Kaneko and Kazuya Yamanouchi, a professor emeritus at the University of Tokyo, are believed to be cool to the idea of resuming beef imports from the U.S.

The research panel of the Food Safety Commission assessed the safety of U.S. beef before the removal last December of a two-year-old import ban imposed after the discovery of the first case of mad cow disease in the United States.