Officials announced small amounts of spinal column parts -- banned along with brains -- were found in a shipment of 700 boxes of beef that has been stored in Tokyo since August.

Yoshinoya Holding Co, operators of a chain of eateries with a specialty of shaved beef served over rice said it will not suspend its business with the facility owned by National Beef, where the banned parts originated.

Grocery chain Daiei Inc. Thursday suspended its orders from the facility, Kyodo News reported.

Beef imports from the United States were suspended in Japan in December 2003 during a widespread panic over mad cow disease.

Imports resumed under new conditions in July 2006.

The Japanese agricultural ministry said it would tighten its inspections of imported beef as a reaction to the recent discovery.