BEIJING, April 29  -- Source control is crucial to eliminating the use of "gutter oil" in China, an expert has said.

Zhu Yi, associate professor at China Agricultural University, was referring to recycled oil made from kitchen waste dredged from gutters behind restaurants and inedible animal oil, as the General Office of the State Council released a guideline to monitor and control the use of such oil Monday.

He said that only by comprehensive supervision and management could enforcers cut off the source of gutter oil, and that the effect of merely punishing violators was limited.

Zhu said that awarding and protecting whistleblowers who report the production, sale and use of the oil would help improve the management of smaller restaurants and oil producers, which he believes are more difficult to supervise.

According to the guideline, more methods will be mobilized to prevent use of the oil, including awards for whistleblowers.

Moreover, catering businesses will be encouraged to install cameras in kitchens, processing workshops and disposal workshops so that kitchen garbage can be traced.

A couple of restaurants in Shanghai have already been answering the call, setting up live streaming in kitchens for customers to watch, showing the restaurants' food safety.