China has prosecuted over 10,000 people in last three years since 2011 for production and sale of substandard and poisonous food, Chinese Supreme People’s Procuratorate (SPP) said here Friday.

According to statistics from SPP, the highest agency at the national level responsible for both prosecution and investigation in the People’s Republic of China, prosecutors also approved the arrest of some 7,000 people linked to manufacture and marketing of food products, Xinhua reported.

Nie Jianhua, SPP vice director in charge of public prosecution, said during a press briefing that illegal workshops, factories and markets were the major sources of problematic food.

Suspects were mainly self-employed business people, farmers or unemployed, he added.

Revealing about a prominent criminal offence concerning food safety, it was stated how a suspect named Liu Liguo sold 100 million yuan’s worth of “gutter oil” made from kitchen waste between December 2007 and July 2011. Some 9 million yuan worth of such unsafe oil entered the cooking oil market.

“Gutter oil” literally refers to recycled oil dredged from gutters behind restaurants as well as inedible animal oil. The oil, which contains carcinogenic substances, is dangerous if consumed.

Liu was given a life sentence in 2013.