Introduction: Waste cooking oil is a general term for waste animal fat, hogwash fat, garbage oil repeatedly heated and collected from sewers of catering enterprises. It is generally divided into three categories: one is swill oil with raw materials from sewers, the other is fried fat with raw materials repeatedly used, and the other is waste animal fat with raw materials.

gutter oil is the general name of waste animal fat, hogwash fat, garbage oil repeatedly heated and collected from sewers of catering enterprises. It is generally divided into three categories: one is swill oil with raw materials coming from sewers, the other is fried fat with raw materials used many times, and the other is waste animal fat with raw materials. The total consumption of animal and vegetable oil in China is about 22.5 million tons a year, and the annual production of gutter oil is 3 to 5 million tons. It is estimated that the gutter oil returned to the table is about 2 to 3 million tons. Personally, I think it should not be so high. If we follow this figure, the oil we eat is 11% gutter oil, and the proportion of restaurants is even higher. The main hazards of gutter oil are: containing aflatoxin and polycyclic aromatic hydrocarbons; Heavy metal ions exceed the standard; Cholesterol exceeds the standard. There are so many harmful substances in waste oil, so testing should not be a problem. The relevant departments can put an end to waste oil by strengthening testing, just as milk powder can put an end to melamine by strengthening testing now. In fact, these indicators are very useful for the detection of waste oil in small workshops, but not in regular factories. There are two reasons. First, the purification of waste oil in regular factories is the same as that of regular vegetable oil, and even more than the extraction of regular vegetable oil, it eliminates the aggregation of polycyclic aromatic hydrocarbons; Second, the sale of gutter oil is not to directly sell pure products to consumers, but to blend different vegetable oils with gutter oil. For example, gutter oil with excessive acidity is blended with ground hook oil with low acidity, so that all indicators meet or approach national standards.

To sum up, it is not difficult to understand that the detection of gutter oil has become a world problem. Now, we mainly detect gutter oil from five aspects: polycyclic aromatic hydrocarbons; Cholesterol; Conductivity (detection of excessive metal ions); Specific gene composition (detecting whether there are animal genes from vegetable oil, I participated in this project and am still doing it); Acid value (symbol of free fatty acid content in fat). But in fact, I think this test is very characteristic of China, and there is little research on testing methods abroad, because it is not testing but policies and regulations that prevent gutter oil from flowing into the dining table abroad. The recovery of waste cooking oil is a very good thing for environmental protection, and it also has market value, which can be used as biodiesel, production chemicals, organic fertilizers and so on.

Businessmen are after profits. It is unrealistic for you to ask every businessman to maintain noble character. Personally, I think it is not how to punish businessmen, but how to guide, manage and help businessmen. The government has an unshirkable responsibility for this, rather than letting the society provide testing methods. In my opinion, the standardized management of waste oil should achieve the following points: Method 1: restaurants and household sewers are forced to install special devices for recycling waste oil. Restaurant waste oil is recycled by specific manufacturers or professional environmental protection companies, and restaurants are not exposed to swill oil at all, and households are recycled by specific manufacturers or professional environmental protection companies at designated points. The government has enacted a waste oil law to prohibit the sale of swill oil and fried oil (especially foreign brands McDonald's and KFC, which use frying in large quantities), and to follow up and supervise them to prevent small workshops from purifying waste oil at low cost. Policy subsidies shall be provided for the sale of waste oil, and price leverage and severe punishment shall be used to guide the flow of waste oil, and subsidies shall be given according to the quantity of waste oil sold by manufacturers. Method 2: Generally the same as method 1, the government directly recycles it at a high price and sells it to waste oil manufacturers at a low price. In fact, my method also refers to foreign methods. We should learn from foreign countries while vigorously inventing detection methods. There is no such policy in our country now, but some local departments have begun to take similar measures. I feel that the operability is not strong and the recovery of waste oil is not thorough enough. If we follow my method, we will never see dirty and smelly slop trucks everywhere (replaced by professional equipment), and we will no longer have to worry about unscrupulous manufacturers selling waste oil to edible oil companies, because they will lose government subsidies (not worth the loss) and face high fines or a situation of losing all their money.

(Author: Yang Guo, the Great Hero of the Condor Heroes)