Lucknow, May 5: Two children, aged 4 and 5, died today after milk served during the midday meal at a Mathura school sent 40-odd pupils to hospital yesterday. Two others are critical.

Government sources said "expired" powdered milk had been mixed with hot water and served at the government-aided primary school on the outskirts of Mathura city, 370km from Lucknow.

"The supplier will be arrested," an official said. "The school principal will also be in trouble for not maintaining the quality of the meal."

Teachers and principals have a standing order to taste any food before it's served to the children, he added.

Last week, parents of children studying in government-aided schools in Mathura had complained that the schools had stopped serving the midday meal for the past several months.

That prompted the state education department to immediately arrange for the supply of midday meal materials to 75 of the district's 94 aided schools.

Chief minister Akhilesh Yadav has asked district magistrate Rajesh Kumar to investigate and report to him soon.

The children began complaining of pain and nausea half an hour after drinking the milk. When they started vomiting, they were admitted to hospital where Ehsan, 5, and Kirti, 4, died.

"The guilty must be punished," state education minister Ahmad Hasan said.

Three other schoolchildren have died in Mathura in the past three years after taking the midday meal.