The Shidax board's opposition to the tender offer by Oisix is "not the unanimous opinion of the Shidax group," a representative of the units said in a letter sent to Oisix and seen by Reuters.
The letter was dated Tuesday.
Later on Tuesday, Unison Capital said it would agree to a tender offer by Oisix if certain conditions were met, and the Nikkei newspaper reported that Colowide Co Ltd, a company mainly engaged in the restaurant business, proposed to take over Shidax's school lunch business.
No further details were immediately available.
(Reporting by Makiko Yamazaki; editing by Kim Coghill and Jason Neely)