Kidney stones diagnosed in boy from tainted milk, biscuits A 21/2-year-old boy has been diagnosed with kidney stones from drinking milk and eating biscuits contaminated with melamine, the seventh child affected in Hong Kong. The boy, who lives in Southern District, was treated for two renal stones after a check-up. Also yesterday, a sample of a mainland-made muscat flavoured Doraemon Chocolate Gummy was found to have 12 parts per million of melamine. The legal limit is 2.5ppm. Another 114 food samples - included milk and milk products, biscuits, chocolates, instant drink mixes, condiments and curry - were satisfactory, the Centre for Food Safety said. Health minister's approval rating drops to record low Public approval of health minister York Chow Yat-ngok has dropped 11 percentage points to a record low of 31 per cent over the past month, according to the University of Hong Kong public opinion programme. Financial Secretary John Tsang Chun-wah's approval slipped 2 points to 41 per cent. The vote of confidence in Chief Executive Donald Tsang Yam-kuen crept up 2 percentage points to 44 per cent. The survey had an overall sample size of 1,007 and margins of error of 2 to 4 percentage points.