The container of a preliminary gutter oil processing workshop in Ninghai county, Zhejiang Province. Photo: Xinhua
A nationwide illegal cooking oil ring has been dismantled by police, the Ministry of Public Security announced Tuesday.
The ring was accused of processing kitchen waste and sewage before packaging and selling the end-product as edible oil.
Police officers in Zhejiang, Shandong and Henan provinces arrested 32 suspects belonging to the network, which had tendrils across 14 provinces.
"Joint campaigns for the first time broke all the links on the chain – from collecting of raw materials, refining and distribution to retail outlets," the ministry said.
This also marked the first concrete evidence that such illegal oil had actually been sold to customers, despite similar reports from two years ago.
In the operation launched in mid-July, police removed six underground producing sites and uncovered two illegal-production lines in the provinces, according to the statement.
The first level of the underground network involves people who buy kitchen waste from restaurants and collect oily sewage from drains.
These "materials" are then brought to a boil and filtered at small workshops before being turned into roughly processed oil.
One of these primary processing centers in Ninghai county, Zhejiang, sold its products to refiners in Jiangsu and Shandong at about 5,000 yuan ($781.44) a ton, according to the ministry.
The refiners then purify the oil in their own facilities, as well as lowering fatty acid content and removing bad odors.
Finally, wholesalers buy the oil from refiners at between 8,000 to 9,000 yuan a ton, lower than the 10,000 yuan a ton paid for legitimate oil.
Police confiscated over 100 tons of gutter oil ready for wholesale after raiding a bio-fuel company, Jinan Gelin Bio-Energy, in Shandong, the ministry said.
Regarding previous claims that gutter oil would not end up on dinner tables as it would cost more to produce than to sell, the ministry said its findings disproved these theories.
Since 2009, "gutter oil" has become a catchphrase in China when referring to the country's food safety problems.
Such false oil is harmful to human health and long-term intake can cause stomach aches, diarrhea or even cancer.
However, due to difficulties in collecting evidence and proving the facts, few gutter oil producers have been brought to justice.
"After being treated, some gutter oil can even meet China's edible oil standards across all major parameters such as fatty acid and peroxide readings," Liu Shipeng, the deputy chief of the Oil Branch of the China Food Association, told the Global Times.
According to him, by applying current national food standards, inspectors cannot tell if samples of oil come from sesame or sewage.
Because of these difficulties, finding producers depends on evidence collected during the manufacturing and sale process, said Zhang Yongjian, a food industry expert at the Chinese Academy of Social Sciences.
"Prosecutors need to prove that their suspect has collected, treated or sold gutter oil," Zhang told the Global Times, adding that suspects in the latest crackdown could face charges of producing and selling food of false ingredients or inferior quality.
Wang Weibiao, a deputy police chief in Ningbo, Zhejiang, told the Xinhua News Agency that the act of collecting gutter materials could be legal if these were used for producing bio-fuels and fodder oil.
He also acknowledged that the processing of kitchen waste still lacks oversight China, leaving space for the development of a "gray industry."
Liu Liguo, owner of the Jinan Gelin company which is under interrogation, told Xinhua that their bio-fuels make little revenue as they have not sold well to petrol stations.
Wuhan Polytechnic University food technology professor He Dongping, a long-time campaigner against gutter oil, estimated that "two to three million tons of gutter oil reaches customers per year."
"Considering that 22.5 million tons of cooking oil are used every year in China, it means you have a chance of eating gutter oil once every ten meals," He told the China Youth Daily.
He urged the creation of testing standards for gutter oil, and called on local governments to shoulder the responsibility of collecting and processing kitchen waste.
The Shanghai government is considering starting a monitoring system to keep track of food waste and to fine restaurants that dump waste into the municipal drainage pipes, according to the city's news portal eastday.com.
Restaurants that improperly dispose of used cooking oil may lose their license in Beijing, the Beijing Times cited a recent municipal regulation as saying.
According to He, it could take 10 years for authorities to stop gutter oil from reaching the nation's pots and pans.
Pang Qi and Xu Tianran contributed to this story