Four people were convicted and sentenced to prison Thursday for producing and selling melamine-tainted milk powder in north China's Hebei Province, a local court said.

Cui Weizhong, legal representative of the Yongxing Dairy Co., was given a five-year sentence for blending 500 kg of melamine-tainted milk powder into the company's products over the past two years, said a spokesman with the People's Court of Xushui County.

The court also fined him 150,000 yuan (23,000 U.S. dollars) and his company 250,000 yuan.

Liu Dan, a company lab technician, was sentenced to jail for three years for assisting in the production of the tainted milk powder, said the spokesman.

Liu was given a 100,000-yuan fine, he said.

The court also sentenced two others, Dang Yao and Mi Pengyong, to three years and 18 months in jail, respectively, for selling the contaminated milk powder to Cui in 2009.

They were both fined 10,000 yuan, said the spokesman.