Most lunch boxes for primary school children are too salty and lack calcium, Department of Health tests of 78 lunches from 19 suppliers have found. All but one sample contained more salt than the recommended level, while the amount of calcium in 77 samples was far below the amount deemed necessary. Three samples - fried noodles, a cheeseburger and a fried beef dish - were found to contain 2,300 to 2,400 milligrams of salt, more than a person should consume in a day. According to Chinese Nutrition Society standards, a primary school pupil should have about 267mg of calcium and 400mg of sodium per meal. The tests were carried out by the department and the Centre for Food Safety in January, four months after the publication of nutritional guidelines on primary school lunches. The department's senior medical and health officer, Leung Wai-man, said most of the samples contained the right amount of carbohydrates and major nutrients, but the high amount of sodium and the lack of calcium were unacceptable. 'We are very concerned that the improper intake of such elements will increase children's risk of suffering chronic diseases,' Mr Leung said. Too much salt has been proven to be a contributing factor to hypertension, heart disease, kidney disease and stroke. Too little calcium can affect the formation of children's bones and teeth. In the tests, 4 per cent of the lunch boxes failed to meet the lower limit of total dietary fibre content, and one-tenth were high in total fat or sugar. Research officer Virginia Tao suggested lunch suppliers choose more low-fat cheese, milk, tofu and dark green vegetables to increase the intake of calcium, and avoid ham, luncheon meat and salted fish, which were often too salty. She said the department was planning to offer more training sessions to cooks who prepared the lunch boxes.