Gutter oil

Gutter oil (Chinese: 地沟油; pinyin: dìgōu yóu, or 餿水油; sōushuǐ yóu) is a term used in mainland China, Hong Kong, Macau and Taiwan to describe illicit cooking oil which has been recycled from waste oil collected from sources such as restaurant fryers, grease traps, slaughterhouse waste and sewage from sewer drains. Reprocessing of used cooking oil is often very rudimentary; techniques include filtration, boiling, refining, and the removal of some adulterants. It is then packaged and resold as a cheaper alternative to normal cooking oil. Another version of gutter oil uses discarded animal parts, animal fat and skins, internal organs, and expired or otherwise low-quality meat, which is then cooked in large vats in order to extract the oil. Used kitchen oil can be purchased for between $859 and $937 per ton, while the cleaned and refined product can sell for $1,560 per ton. Thus there is great economic incentive to produce and sell gutter oil. It was estimated in 2011 that up to one in every ten lower-market restaurant meals consumed in China is prepared with gutter oil. This high prevalence is due to what Feng Ping of the China Meat Research Center has made clear: 'The illegal oil shows no difference in appearance and indicators after refining and purification because the law breakers are skillful at coping with the established standards.' The first documented case of gutter oil in Taiwan was reported in 1985. In a subsequent investigation, 22 people were arrested for involvement in a recycling oil ring over 10 years based in Taipei. The worst offender was sentenced to 7 years in prison. The first documented case of gutter oil in mainland China was reported in 2000, when a street vendor was found to be selling oil obtained from restaurant garbage disposals. In September 2012, an ongoing investigation into the suspected use of gutter oil as a raw material in the Chinese pharmaceutical industry was revealed. A scandal involving 240 tons of gutter oil in Taiwan affecting hundreds of companies and thousands of eateries, some of which may have been exported overseas, broke in September 2014. The collected waste oil is sold to local workshops or small factories for cleaning and packaging. When sold to workshops it is often transported on the back of bicycles by peddlers who are paid a monthly wage; afterwards, the oil is held in 200-liter barrels at the workshops until it is processed. On other occasions the oil goes to industrial cooking oil refineries for further processing before it finally reaches its end purpose. The industrial oil refineries are usually legitimate producers that sell the processed oil for use in the chemical or energy industries. Gutter oil is perfectly suitable as a raw ingredient for producing soap, rubber, bio-fuel, and cosmetics. However, the refiners can also have other intentions as the prices attained by selling it as cooking oil are much higher than if it is sold to the chemical or energy industries. There are few formal rules or protocols in place to prevent purchases from or sales to entities intending to use the oil for human consumption, so it is very easy for individuals or wholesalers to purchase oil from these industrial refineries and then resell the oil to restaurants or to end consumers. There have been some cases where the industrial oil refiner packaged the oil under a unique brand name and sold it as legitimate oil in retail outlets as opposed to just selling directly to restaurants. Some lower-market restaurants have long-term purchase agreements with oil recyclers for selling their used oil.