School dinners

According to Sunday's Sunday Times, following on from the TV series "Jamie's School Dinners", the average amount spent by a school on the lunches they provide to their pupils is 37p a day. The average amount collected from parents (or claimed from LEA for free school meals where children qualify), however, according to the article and confirmed by some phone calls to parents of school aged children I know is around £1.75-2 per pupil per day. Where's the rest of the cash going? Even if the 37p is purely for the food delivered to the door I find it impossible to believe that they are spending £1.38 per pupil per day on reheating the food, serving it up and washing the utensils afterwards. I know how little those kitchen assistants and lunch supervisors earn, it's a pittance (I know people who work in school kitchens and lunch rooms). I'd be surprised if it cost more than the 38p, so that's a quid, at least, going astray for each pupil each day