"The application for probation and exemption from criminal punishment will be reduced, unless there are statutory mitigating circumstances," said Zou from the Shanghai High People's Court.

For such cases, a fine worth twice the production or sales amount will be imposed, according to the interpretation.

"I think the supreme court's intention is to ruin the criminals economically and deprive them of the capital to gain illegal profits again and deter other lawbreakers," Zou said.

Shanghai has struck hard at such crimes in recent years. Seventeen people were imprisoned in 2010, and the number last year was 86, according to statistics from the court. Sentences, as well as fines, have increased, Xu said.

On Feb 28, the People's Court of Shanghai's Huangpu district sentenced two people who used gutter oil, or recycled cooking oil, to make a soup base for hotpot to three years and six months in jail and a fine of 200,000 yuan ($32,630).

"The fine was basically a record high, but with the new rules, the fine will grow higher in the future," Xu said.

But some criminal law experts said the punishment remains light compared with some foreign countries.

"Anybody who has a criminal record in terms of food safety will get a lifetime ban from the industry in some countries," said Liu Xianquan, dean of the Law School of East China University of Political Science and Law.

"Nevertheless, the improvement is appreciated anyway," he said.

The food safety situation remains stable in Shanghai. Seven mass food poisoning incidents happened in 2012, but no one died.