A melamine producer and a dealer are on trial in Shijiazhuang, capital of northern China's Hebei province.
The hearing is underway at the Shijiazhuang Intermediate People's Court.
Zhang Yujun and Zhang Yanzhang were accused of illegally concocting and selling the so-called "protein powder," which was mainly composed of melamine and malt dextrin. It was then added to raw milk to make it appear high in protein content.
Police said they found their illegal production workshop in the outskirts of Jinan, capital of eastern China's Shandong province. The two are accused of producing 600 tons of the fake protein powder from September 2007 to October of this year.
The workshop is the largest source of melamine in the country, police said.
The Shijiazhuang-based Sanlu Group was at the center of the tainted milk powder scandal. Other major Chinese dairy brands such as Mengjiu and Yili were also found to have melamine contents higher than the national food safety requirement in some of their products.
Sanlu stopped production on Sept 12. On Dec 19, the company borrowed 902 million yuan (about US$132 million) to pay the medical fees of children sickened by its melamine-tainted baby formula and to compensate the victims.
Sanlu, facing 1.1 billion yuan of debt, has filed a bankruptcy petition.
(Xinhua News Agency December 26, 2008)