China, one of the world's largest food consumption markets, needs stricter national-level regulations to streamline its management of food safety, along with better public oversight of the country's superlarge and complex food supply chain, industry experts said on Tuesday.

Their comments came after some media reports last week said that stockpilers including China Grain Reserves Group, or Sinograin, used the same tankers to transport edible items, such as cooking oil and syrup, after delivering liquid fuels produced from coal.

A report published in the newspaper The Beijing News said that mixed use of tankers for transportation of food and chemicals has become an "open secret" in the industry, which has sparked food safety concerns nationwide.

On Tuesday, the office of the food safety commission under China's State Council said it has organized the National Development and Reform Commission, the State Administration for Market Regulation and other authorities to set up a joint team for a thorough investigation into the improper use of tanker trucks in the transportation of edible oil.

Companies and individuals who are found responsible will be severely punished, and violation of the law will not be tolerated, it said.

The findings of the investigation and handling of the matter will be promptly disclosed, according to the office.

Zhu Yi, a professor at China Agricultural University's College of Food Science and Nutritional Engineering, said that liquid fuels, which have a high percentage of toxic hydrocarbons, could pose serious health risks if consumed even in negligible quantities, as long-term exposure could lead to poisoning.

Deng Manyin, joint partner at Beijing DHH Law Firm, said mixed transportation is "undoubtedly illegal" according to the country's Food Safety Law.

The law clearly states that containers, tools and equipment used for storing, transporting and handling food items must be safe and clean, and they should also be equipped to prevent contamination, he said.

It further stipulates that food items must not be stored or transported with toxic or harmful substances, Deng said.

"To ensure food safety, it is evident that self-examination by companies alone is insufficient. Preemptive regulatory work and the implementation of laws and regulations are among more critical steps that should be taken," he added.

Sanhe Hopefull Grain and Oil Group, which is based in Langfang, Hebei province, and China Grain Reserves Oil and Fat (Tianjin) Co, a subsidiary of Sinograin, are among enterprises implicated in the scandal.

In their latest responses, market regulators in both Langfang and Tianjin said that investigations are underway and they will inform the public of the results in due course.

Sanhe Hopefull Grain told the media on Monday that the company is probing the matter, but the tankers involved didn't belong to it.

In a Sina Weibo post on Saturday, Sinograin said it had ordered a "thorough self-inspection", including investigating whether transportation carriers leaving and entering its warehouses were compliant with food safety regulations.

Yang Xin, an assistant researcher at the Chinese Academy of Social Sciences' Rural Development Institute, said, "Chinese authorities have made great efforts to ensure food safety, but they need more stringent regulations to oversee the whole industry chain ... as well as more punitive and incentive systems to ensure those regulations are actually implemented."