Producing powdered milk contaminated with the industrial chemical that had killed six babies in 2008 led to seven people being arrested by police in North China, according to the state press.
Wang Zhigang, an official at the Jinfulai dairy company in Shanxi province, was among those arrested for allegedly putting excessive amounts of melamine in the milk powder, the Procuratorate Daily reported.
The 26 tonnes of tainted product had also been made with unsold milk powder past its sell-by date, and then distributed in the central provinces of Hunan and Henan, it added.
Two people were executed for their role.
Melamine, normally used in plastics and other products, was added to milk to make it appear to have a higher protein content.
China has repeatedly said that all tainted products were seized and destroyed at the time, and that there was no further public health threat, but reports on contaminated items on store shelves have continued to trickle out.
In July, authorities said they had found 25,000 tonnes of milk powder tainted with melamine earlier this year.
Last week, China again pledged to punish people guilty of food safety crimes, calling for the death penalty to be applied in cases where culprits "deserve" it, state media reported.