The suspects have been charged with manufacturing and selling fake and substandard products, as well as manufacturing and selling toxic and hazardous food, a written statement issued by the Intermediate People's Court in Ningbo said.
"Gutter oil" refers to recycled oil made from kitchen waste dredged from gutters behind restaurants in China.
Prosecutors said that from December 2007, seven of the defendants refined substandard oil from waste cooking oil and sold it to wholesalers as edible oil, seeing total sales reach up to 99.2 million yuan (USD 15.6 million) said the statement.
The wholesalers, including companies and individuals, mixed the gutter oil with edible oil and sold the mixture to retailers, reaping profits in the process.
The Ministry of Public Security said in April that it has stepped up a crackdown on underground workshops that produce gutter oil.
The oil has been deemed unsafe for consumption, as it may contain carcinogenic substances, state-run news agency Xinhua reported.
