The farm ministry has begun developing a system to numerically label every package of beef to show consumers the birthplace of the cow it is from and the farms where it was raised, ministry sources said Sunday.

The introduction of the system, dubbed "traceability," is aimed at restoring public trust in beef in the wake of the discovery in September of Japan's first case of mad cow disease, the sources said.

The Ministry of Agriculture, Forestry and Fisheries has had trouble tracing the cows that were raised at the same farms that bred the cow in question, which was born in Hokkaido and was later sold to a farm in Chiba Prefecture.