The U.S. government notified Tokyo that about 1.3 tons of beef from 21-month-old cattle -- above Japan's import limit on the cattle age -- was in 21 tons of meat exported to Japan since November, and processed at Moyer Packing Company of Smithfield Beef Group, a subsidiary of Smithfield Foods since November.

A computer programming mistake at the U.S. firm led to the erroneous shipments, the statement said.

Japan suspended beef imports from the facility and ordered two Japanese importers, Marudai Foods and Shinwa Ox to recall the beef.

The beef did not include risky materials, such as spinal cords, thought to carry the risk of spreading the mad cow disease.

Violations of Japanese import regulations concerning U.S. beef shipments have taken place since Japan conditionally lifted its import ban in 2006, but have been discovered before the meat reached consumers.

Source: Reuters