Operation of a kindergarten in north China was temporarily called off after more than 80 children and teachers there were sickened by food poisoning last month, according to the local authorities.

Elfin Kindergarten in Baotou City, Inner Mongolia Autonomous Region, closed on Sept. 25 for rectification in line with a government order, a day after dozens of children and teachers showed symptoms of fever and vomiting, the health bureau of Baotou said Friday.

Hospitals had treated more than 80 children and teachers from the privately-owned kindergarten as of Sept. 29, but none of them showed critical symptoms.

Latest tests conducted by officially designated laboratories blamed the food poisoning on a certain type of bacteria in the supper the victims had eaten.

Investigators were still trying to find out how the bacteria contaminated the food.

The Elfin Kindergarten has more than 400 students and teachers. More than 280 children dined at the kindergarten when the incident happened on Sept. 24.