More than 300 children have been hospitalized with food poisoning at a kindergarten in northwest China, according to state media.

Xinhua news agency reported Thursday, Sept. 20, that 260 children ages between 4 and six, suffered food poisoning Wednesday from a meal at Shiyan Kindergarten in Wuwei City. The symptoms they presented were vomiting, fever and stomachaches.

The number has since risen to 307 children, according to reports. The food poisoning was reportedly caused by a breakfast of porridge and buns at their kindergarten.

Xinhua reports that the initial investigation suggested the food poisoning was a result of the children eating pork infected with diarrhea-inducing bacteria.

The little ones’ illness was thankfully not severe, as they were treated and gradually allowed to leave hospital and return to their homes. As of mid-afternoon Saturday, most of the children had left the four different hospitals were they were being treated, says Xinhua.

The news agency informs that the Wuwei Municipal Health Bureau took immediate measures, organizing a group of pediatric specialists to treat the sick children. The management of the kindergarten initially refused to comment and later said food poisoning was very rare in the institution.

It was reportedly one of the teachers that revealed the young patients had consumed porridge and buns on Wednesday morning.

While there was no more of the respective meal left for analysis, local health workers said the dishes had been sent for laboratory tests, on suspicion of inadequate sterilization, reports Xinhua.

Health authorities of northwest China's Gansu Province, where Wuwei is located, said on Sunday that thirty-four children remained hospitalized.

“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.