A Shanghai restaurant owner was sentenced to three and half years in prison and her employee was sentenced to one year after they were found guilty of manufacturing and selling toxic or harmful foodstuff by using gutter oil, or recycled cooking oil, in hotpots served in their restaurant.

The pair was sentenced by a court in Shanghai's Huangpu district on Thursday. It is the first time restaurateurs in Shanghai have faced criminal charges for using gutter oil.

Zheng Pin, 38, and her nephew Zheng Wei, 26, admitted to using gutter oil to cut costs since last June.