Thirty-four children remain hospitalized for food poisoning after they ate meals in their kindergarten on Wednesday, said health authorities of northwest China's Gansu Province on Sunday.

A total of 307 children, all from the Shiyan Kindergarten in Wuwei City, showed symptoms of vomiting, fever and stomachaches after they had porridge and buns for breakfast prepared by the school eatery on Wednesday. They were sent to four local hospitals for treatment.

"By 9:00 PM on Saturday, 273 children had been discharged from? hospital, and the remaining 34 are receiving further treatment, all in stable condition," said a spokesman with the Wuwei City Health Bureau.

Preliminary investigations show that the children ate the pork infected with "Shigella," a genus of bacteria that can cause sudden and severe diarrhea in humans.

"There is no possibility of new poisoning cases as the bacteria has passed the latent period," the spokesman said.

Local authorities are investigating how and when the pork was infected with the the bacteria, he said.

The Shiyan Kindergarten has now 502 registered preschoolers, said Ning Shengqin, head of the kindergarten.

"It (food poisoning) is a rare and occasional incident," she said.

(Xinhua News Agency September 23, 2007)