New technology will allow parents to check online what food their children buy at school and whether it matches strict new dietary standards.
Education authorities and school caterers are already investing in new computer software to ensure that the meals and menus they offer meet tough nutritional rules from 2008.
Now The TES has learned that several are planning to marry up the technology with cashless, swipe card or fingerprint systems operating in school canteens, to measure the nutritional content of what pupils buy.
A detailed breakdown of a child's lunch would then by made available to parents over the internet or via computer print outs. Their diet over a day, week or month would be rated by a traffic light system with green showing they met the nutritional standards, yellow that their choices came within 10 per cent and red that they were outside the guidelines.
Margaret Morrissey from the National Confederation of Parent Teacher Associations, welcomed the idea provided the costs were not excessive.
"Children will hate it because there will be no more 'I am not having vegetables tonight because I had them at school'," she said.
The software, costing up to pound;10,000, includes databases with nutritional details of the ingredients and foods likely to be used.
Authorities and caterers input their planned recipes and menus into the system which then tells them how they rate against the Government standards.
The standards, which are due to be introduced in September 2008 in primaries and secondaries, and special schools a year later, specify levels of energy, protein, carbohydrate, fat, saturated fat, fibre, sodium, vitamins A and C, folic acid, calcium, iron and zinc.
More than 50 local authorities have signed up to nutritional analysis software being offered by Fretwell-Downing Hospitality.
Andrew Markwell, its business development manager, estimated 30 per cent of English schools also had cashless card systems and said it was working with at least four authorities to make nutritional information on pupils'
choices available to parents.
"Parents are getting more and more aware of what goes into their children's diet and they want as much information as they can get," he said.
Northamptonshire council says at least of four of its secondaries will be able to supply parents with information from September.
Ruth O'Donnell, the authority's healthy food strategy manager, said it would allow parents to see if pupils had spent their dinner money outside school and could help those with particular health problems.
But Marcus Buck, 17, an English Secondary Students' Association council member and pupil St Edward's RC college, Liverpool said: "It sounds quite big brotherish. This could go the other way by putting students under too much pressure.
"They might get food that is healthy and not eat it or just go to shops outside the school. It doesn't really prepare them for the world outside where they will have to make their own decisions."