Owners and staff members at three restaurants in eastern China have been jailed for using waste cooking oil to make hotpot, according to a news website.
More than 10 people working at the eateries in Wenzhou in Zhejiang province were given sentences ranging from eight months to just over 2 and a half years, 66wz.com reported.
The restaurant owners were given the stiffest jail terms, according to the article.
The group was arrested last year in a government's food safety campaign. Some suspects were caught by police fetching waste oil, also known as "gutter oil", from backstreet drainage near the restaurants.
They reprocessed the waste oil at small workshops in remote suburbs and sold it back to the restaurants for a low price.
The business was carried out under the instructions or consent of the restaurant owners for months, the report said.
There were no immediate indications that the convicted would appeal against their sentences.
Chinese media have regularly reported on cases of "gutter oil" being used in restaurants and Sichuan food eateries which use a lot of chilli oil have often been involved.
A large Sichuan hotpot sometimes contains more than 1kg of chilli oil.
The report said some of the restaurants in Wenzhou were very popular, generating revenue of more than 1.5 million yuan (NZ$290,000) a month.
- South China Morning Post