At least 19 students of a government-aided high school at Pernem taluka in Goa fell ill after eating the mid-day meal on Saturday, officials said.
While a girl was hospitalised at a primary health centre in Tuem, nearly 40 kms from here, rest of the students of the Kamleshwar High School were discharged after initial treatment, they said.
The girl suffered bouts of vomiting after consuming the meal while others felt uneasy, the officials said.
Though the girl is reported to be out of danger she is under observation.
"It is yet to be ascertained whether the incident happened due to food poisoning," an official said.
The affected kids are students from class V to class VII, he said.
Initial reports said that a spider was found in the meal but the official dismissed them as a "rumour".
The job of serving the mid-day meal was assigned to an NGO, Brahmanandacharya Self Help Group. The concerned NGO has also been serving the meal to 13 primary schools and eight secondary schools, officials said.
This is the second such incident which has hit the state during this week.
Earlier this week, around 22 students from St Joseph High School were referred to the hospital due to suspected food poisoning after eating the mid-day meal.