Officials warn of unhygienic summer eatery after school emergency.
Sixty-two students were sent to hospital with symptoms of food poisoning Thursday.
The students from Shanghai Xinzhong Senior Middle School said they became ill after dinner or breakfast at the school's cafeteria.
No one was in a critical condition Thursday night and most had gone home after treatment.
Officials from Zhabei District Health Supervision Agency are investigating.
The cafeteria was shut at noon Thursday and the supervision agency took samples from the food for analysis.
The result is expected to be known in three days, said Li Zheng'an, an official with Xinzhong, a boarding school in Zhabei District.
School officials checked every class after getting the first report and took sick students to hospital, he said.
Huang Qiong, an official at Tongji Hospital, said the first group of 16 students arrived at the hospital at 9:15am.
"By noon, a total of 62 students in six groups had arrived at our hospital with symptoms of fever, diarrhea, bellyache and vomiting," she said.
"Twenty-one were given saline drips and have recovered. Only four students with high fever will be kept in overnight for further observation."
He Xiaojing, 17, was one of the four most serious patients.
"I felt headache and stomachache this morning after eating breakfast in school," she said. "I was checked with a temperature of 40.3 degrees Celsius when I arrived at the hospital."
Local health authorities said there is an increasing incidence of food poisoning in the city and warned residents must be aware of food safety and hygiene, especially in summer. Last Thursday, 88 migrant workers from two factories in Fengxian District were sent to hospital with food poisoning.
Officials found pesticide leftover on the green vegetable in their lunch.
"We have drawn a lesson from the incident and tightened inspection on all vegetable producing and selling facilities," said Xu Jianjun at Fengxian District government.
Shanghai Health Supervision Agency said last month that nine big food poisoning incidents caused by eateries' mismanagement had occurred this year.
The agency said many incidents are because of limited working space, dirty dishes and improper operations.
(Shanghai Daily June 18, 2004)