HONG KONG - A 12-year-old Hong Kong boy has developed kidney stones after drinking milk laced with the industrial chemical melamine, authorities said Thursday.

The boy first visited hospital in December and was admitted on January 2, the Centre for Health Protection said in a statement.

A renal stone was found in his left kidney and the boy, who had a history of consuming milk contaminated with melamine, was discharged seven days later in a stable condition.

It takes the total number of melamine cases in Hong Kong to 14, the centre said.

The latest case was revealed on the day a Chinese court sentenced two men to death and gave stiff jail terms to 10 others over the scandal that last year killed at least six babies and left 294,000 others ill in the mainland.

It also led to recalls across the world of foods containing Chinese dairy products, and renewed worries about the safety of the country's huge agriculture industry.

The chemical was used to give dairy products the appearance of a higher protein content than they actually have.