OSAKA -- Farm ministry officials on Friday searched Nippon Food Inc.'s Osaka unit, which was implicated in the defrauding of a state-run beef buyback program, ministry officials said.

Kansai Company, located in Osaka's central Midosuji district, oversees business operations in western Japan for Nippon Food, a subsidiary of Nippon Meat Packers Inc., better known as Nippon Ham.

The officials also questioned Hiroshi Ohigashi, a senior managing director of Kansai Company, in connection with the fraud, they said.

Ohigashi is believed to have been informed by officials of Kansai Company's sales office in Himeji, Hyogo Prefecture, that the Himeji office had labeled imported beef as domestic and sold it to the government under the buyback program, the officials said.

The Agriculture, Forestry and Fisheries Ministry also plans to search the head office of Nippon Meat Packers, also based in Osaka, to determine whether the parent firm was involved in the fraud, ministry officials said.

The ministry also plans to question Heihachiro Azuma, vice president of Nippon Meat Packers and also president of Nippon Food.

Nippon Meat President Hiroji Okoso has admitted that Nippon Food packaged imported beef as domestic beef to receive government subsidies implemented after mad cow disease hit Japan last September.

The buyback scam took place at the sales office in Himeji, prompting ministry investigators search for evidence at Kansai Company, which overseas the Himeji office, according to ministry officials.

Nippon Food officials have said Kansai Company staff members uncovered the scam in February through an internal probe, apparently prompted by revelations of a similar scam at Snow Brand Foods Co., a Snow Brand Milk Products Co. unit, which was closed in April.

Ohigashi was informed in February about the internal probes findings, the officials said.

It is not known whether the fraud was reported to top managers at Nippon Meat Packers, including Okoso and Azuma.

Ministry investigators searched the Himeji office Thursday.

Shunji Tanaka, a section chief at Nippon Food's Himeji branch, told reporters Thursday that he ordered the deception.

"There was no instruction (to do so) from the parent company," he said.