Tokyo--Japan has lifted its ban on two U.S. beef packers, Smithfield Beef Group and National Beef California LP after recognizing their efforts to improve safety measures following unauthorized shipments containing parts that could potentially carry BSE.

The Agriculture Ministry said Friday that it has resumed imports from the Smithfield Beef Group and the National Beef California LP, effective immediately.

Japan halted shipments from the two plants earlier this year after finding parts banned under a bilateral trade pact. Japan imposed a ban on U.S. beef imports in 2003 after the first case of mad cow disease was found in the United States. Shipments resumed in 2006.

But shipments from the Smithfield plant were suspended in January after meat from a 21-month old cow was found. Japan halted imports from the National Beef plant in April after finding a spinal cord in its shipment.

The ministry said its onsite inspection in August at 10 authorized U.S. meat packing factories, including the two that had been suspended, confirmed that they had taken measures to prevent banned parts from slipping into boxes for shipment to Japan.