Disclaimer: the photos in this post show the cleaning of an cooking oil production site and this site does not necessarily relate to the practises described in this post.
Labelled as “gutter oil” or “swill oil” by the Chinese, the reuse of cooking oil was, and food safely still is, a hot topic one year ago. Cooking oil can be divided in three types:
First, in its most narrow definition, it is oil that is being extracted from leftovers in restaurants and hotels, including what can be extracted from swill or from the floor. It also includes oil that can be extracted from the sewer. The second is the oil made from animal fat, mainly from pork. The third type is the oil that has been used for frying food.
Various scandals related to bad quality and contaminated cooking oil have made headlines in recent years. In addition, the frequent use of overcooked and too often reused cooking oil is said to cause cancer. In July 2010 the government issued an order to crackdown on the black market trade of illegal cooking oil and at the same time invest more in the recycling of cooking oil for other (industrial) purposes.
Apart from the use of cooking oil at home, the typical lifecycle of the oil starts in restaurants. At higher end restaurants, the oil is not used for too long. There is a market for this cooking oil: when collected it is refined and sold to lower end restaurants. The same goes for canteens in factories and schools.
Once the cooking oil is not deemed fit for human consumption it can be used for producing food for livestock. Other uses can be found in the mining of minerals and at chemical plants.
The collection and return into the food chain of “swill oil”
In cities, people often see this scene: a farmer driving a small truck full of swill (slops), moving slowly in the streets, the swill is dripping all the way and spreads a rancid smell. The content of the truck is collected from the waste water reservoirs in restaurants and from the food left overs. It contains, next to cooking oil, all kind of other ingredients like detergent and food remains.
After dinner time, “swill trucks” can be seen in front of hotels and restaurants for this collection. The swill is transported to the outskirts of the cities for further processing into an oil extract. This oil extract is sold to clients who use it to produce cooking oil for the market again. It’s said there are thousands of such installations on farms in the Beijing area.
At many places in the city the oil extracts are turned into cooking oil for the market again. Some of these businesses exist for several generations. According to one owner, the sales have been especially good over the last 10 years. The production of a barrel of recycled oil, based on the oil extracts, takes about three days. The selling price is around 5,000 RMB per ton, with a profit of around 1,000 RMB per ton for the producer.
Some producers hide the origin of the from swill extracted oil by blending it with one third of salad oil and one third of palm oil. This is then sold as genuine cooking oil.
It is estimated that in China the amount of wasted cooking oil that returns to the table is around 2 million to 3 million tons per year. The total consumption of cooking oil extracted from animals and plants is around 22.5 million tons a year. In other words, around 1 in 10 meals is prepared with cooking oil that has been recycled from waste.