Agnish Ray missed school for more than a week last month. What began with mild fever and a stomach ache took a slow painful turn, gradually confining him to bed for days and costing the Class VII student of The Cambridge School precious preparation time before the final exams.

Children become more vulnerable to food poisoning in summer and the incidence goes up by 20 to 30 per cent in the city at this time of the year, doctors said. The reason: cockroaches and rodents that seem to have a free run of the house.

"Decayed food leads to increased cases (nearly 30 per cent) of diarrhoea and gastro-intestinal trouble among kids around this time. The first tell-tale signs are stomach ache and vomiting. Parents should not ignore these and immediately start giving ORS to kids to prevent fluid loss," said Pratim Sengupta, consultant physician and nephrologist at Belle Vue Clinic. Healthy children, too, should drink lots of water to keep indigestion at bay, he added.

Keya Khemka was left wondering what made her daughter Prisha, a Class V student of Modern High School for Girls, fall ill in spite of eating healthy. "I was surprised she had this sudden attack of stomach bug when I only give her homemade food," the mother said.

Cockroaches are one of the main causes of food contamination and poisoning, especially among children, in summer. Leaving unwashed dishes in the sink after dinner or not cleaning the dining table properly after a meal are invitations to cockroaches and other insects for a late-night party!

"The next morning at breakfast, a child could pick up something from the table. In some cases, where kids are fed by help, strict hygiene may not be maintained. All these can lead to food poisoning even if the child is eating apparently healthy meals," said Anirban Chakraborty, a consultant physician at Narayana Superspeciality Hospital.

Chakraborty has treated at least two or three patients of food poisoning over the past month. "Cockroaches and its faeces are the main cause of allergies and asthma among kids in summer," he warned.

Some parents are more careful. "I got a pest control done in my house last month before it got too hot, as a preventive," said Devaleena Guha Ghosh, whose daughter Swaha studies in Class IV at La Martiniere for Girls.

City schools, too, are taking steps to ensure hygiene and health. At both the Park Street and Salt Lake branches of Apeejay School, the health and wellness club members and an in-house nutritionist are keeping watch over the food served in the canteens.

"We are also checking the children's lunch boxes and helping parents with suggestions about the kind of food they should prepare for their wards. Food poisoning is a major reason why kids miss out on school around this time," said principal Rita Chatterjee.

Students of Mahadevi Birla World Academy are counselled by the school doctors on proper eating and hygiene habits. "The children have been educated about safe tiffin options," principal Anjana Saha said.

St. James has also stepped up inspection of the canteen. "We see to it no food is recycled," principal T.H. Ireland said.