UPDATE 1-Alfa says better results needed to spin off Alpek unit

Mexican conglomerate Alfa will only spin off its 82%-owned petrochemical subsidiary Alpek when the financial results of Alpek and food unit Sigma improve to an appropriate level, company executives said on Tuesday. Alpek has its own shares that trade publicly, but its results remain consolidated into Alfa's structure. Alfa reported after markets closed on Monday that it swung to a loss in the third quarter, dragged down by Alpek's poor performance.