Officials of the Obihiro public health office in Hokkaido ordered a new safety inspection of a Snow Brand Milk Products Co. factory Tuesday after finding bacteria at the plant.
Operations at the Taiki factory have been under suspension in connection with a massive outbreak of food poisoning in August.
The officials said the suspension order was to be lifted Tuesday if no bacteria were found, but now operations are likely to remain suspended until Thursday.
On Aug. 23, the Hokkaido Prefectural Government ordered Snow Brand to halt operations at the Taiki plant indefinitely after discovering enterotoxin, a bacterial toxin, in samples of powdered skimmed milk produced there.
In September, Snow Brand presented to the prefecture plans to improve safety at the plant, including a manual to deal with similar problems.
Local health authorities on Sept. 3 allowed the factory to conduct test production as a step toward lifting the suspension order.
The powdered skimmed milk was an ingredient in four dairy products made at Snow Brand's Osaka plant that caused widespread food-poisoning in June and July, making some 15,000 people ill.