Police seized more than 3,000 tonnes of illegally manufactured cooking oil last month in raids on 13 underground workshops and licensed factories on the mainland.
More than 100 suspects involved in the national production and distribution network were arrested.
Residents of a village in Jinhua, Zhejiang, had reported a suspicious workshop to local police in October, the Ministry of Public Security said on its website yesterday.
Sumeng residents said a strong smell of animal fat often wafted from a farmhouse in the village.
Police officer Shao Wenzhong told China Central Television that a site investigation had turned up mainly empty, stained barrels. Officers found bricks of animal fat in the courtyard, which led them to a nearby slaughterhouse.
Fu Xuejun, a police officer in Jinhua's Jiangnan district, told the broadcaster that the workshop was using animal organs - such as stomachs, intestines and livers, some of which were rotting - to make oil. The final product was physically and chemically different from the 'gutter oil' illegally produced by collecting discarded oil from restaurant waste.
