Several students at the Rajkeeya Girls Senior Secondary School had already eaten the "khichdi" served to them on Thursday before the baby snake was spotted in the rice and dal mix.
One girl vomited and others complained that they were feeling unwell.
The principal, Braj Bala, said the meal was supplied by ISKCON. "As soon as the snake-like insect was found, we stopped all children from eating it and complained to ISKCON and to senior officials in the education department," she said.
Other schools that had been provided the same meal were also informed that it should not be served.
The quality of mid-day meals - or free lunch provided by the government under a scheme to draw the poorest to schools across India - has been notoriously erratic, with reports of dead rats and insects found in them.
Some students alleged that the food was often stale.
ISKCON has been quoted in reports as saying that its food is cooked properly and in the cleanest of kitchens. An official said the food was checked before being handed over. The problem, he said, was that at the schools, the food was kept uncovered, in the open.