Five people, including former officials of Marubeni Chikusan Corp., pleaded guilty Monday to charges that they fraudulently mislabeled imported chicken as prime domestic poultry.

Marubeni Chikusan, based in Tokyo, is a subsidiary of trading house Marubeni Corp.

The five defendants, including Akihiro Yoshikawa, 47, former head of Marubeni Chikusan's Tohoku region marketing department, and the former chief of the firm's Sendai branch, Yasushi Sato, 45, are accused of fraud and violating the Unfair Competition Prevention Law.

In their opening statement at the Sendai District Court, prosecutors said the falsification began around 1991, when Sato lied to clients by saying he could provide them with prime domestic poultry on a continuous basis.

Initially, the officials sold thawed frozen chicken meat as fresh meat, according to prosecutors. Then, starting around 1997, they began passing off meat from Brazil as domestic poultry.

In an effort to avoid discovery, officials of the firm wiped the water off the thawed meat, and limited sales to large-scale retailers that purchased from Marubeni Chikusan in bulk.

The five defendants are accused of defrauding clients out of some 1.4 million yen between September and December 2001 by repackaging roughly 41.7 tons of imported chicken meat in bags stamped "domestic" and then selling them. The fraud charge applies to about 2.2 tons of this amount.

The other three indicted in the case are Tatsuta Goto, 42, former acting head of the Sendai branch, Shinya Chiba, 30, a branch employee, and Yuji Sugiyama, the 54-year-old senior managing director of the meat processing firm where the repackaging took place.