Saibal Dasgupta | TNN Beijing: The Chinese government finally claimed some success in tackling the scandal concerning contaminated baby foods that has resulted in the death of another infant, taking the toll to two, and caused severe sickness in at least 600 others. On Monday, it announced the arrest of two persons for allegedly adding melamine, an industrial chemical, to the milk powder. But questions remain on whether investigators have been able to crack down on the entire network that was involved in the scandal. Investigators are focusing only on milk collection centres instead of looking into the role played by the main company and its factories. The milk powder supplied by the concerned company, Sanlu Group Co, has resulted in kidney stones in 580 babies who consumed it. Police officials have seized 60 bags of white powder, which contained high levels of melamine, in Hebei. The scandal has raised fresh questions about food safety in China, which suffered bad publicity over exports of dubious quality foods to Japan and other countries. Police have arrested two brothers with surname Geng, who ran a milk supply centre in Hebei province supplying three tonnes of milk to the milk powder producer, Sanlu Group Co. They have been accused of using this chemical to cheat the testing laboratories by showing higher levels of protein in milk. Melamine has the property of raising protein levels although it is highly toxic. This is the first arrest to be made in the case, which has resulted in countrywide inspections of all milk powderproducing companies and distribution outlets. Li Changjiang, head of the General Administration for Quality Supervision, Inspection and Quarantine, said the contamination took place at the milk-collecting stations. The police have detained 19 other people who worked at a private milk collection centre. and are questioning another 78 people. Sanlu is partly owned by the New Zealand dairy farmers