NANJING - About 40 students at a middle school in East China developed food poisoning symptoms after eating lunch at school canteen on Monday, local authorities said.

The students at the Shunhe middle school in the city of Huai'an in Jiangsu province were then sent to a local hospital for emergency treatment, the city government said in a statement.

By late afternoon, none of the students were in life-threatening danger, it said.

Local health and education authorities are investigating the exact cause of the poisoning.