SAPPORO -- The Hokkaido Prefectural Government on Wednesday ordered Snow Brand Milk Products Co. to suspend operations for an unspecified period at its plant in Taiki, Hokkaido, after discovering a bacterial toxin in samples of powdered skim milk produced there, officials said.

The prefectural government's health officials have detected up to 20 nanograms per gram of enterotoxin A -- the toxin produced by the staphylococcus aureus bacterium.

The concentration in the samples is some five times higher than the levels detected at the company's Osaka factory, the officials said. One nanogram is one-billionth of a gram.