In fact, the transformation of waste oil into edible waste oil is a general concept, which is a general term for all kinds of inferior oils in people's lives.
Waste oil can be divided into three categories:
One is gutter oil in a narrow sense, that is, oily floating objects in sewers or leftovers from hotels and restaurants (commonly known as swill) are simply processed and refined;
The second is the oil produced by the processing and refining of inferior pork, pig offal and pig skin;
Third, the oil used for fried food should be reused after being used more than the specified number of times, or after adding some new oil to the oil.
When law enforcement officers check, they use the test paper for rapid detection of edible oil rancidity to compare whether the peroxide value and acid value of the detected oil exceed the standard, and once it exceeds the standard, it can be determined that it is a problem oil.
Advantages and disadvantages of waste oil
In favor: producing biodiesel from waste oil. According to experts, after the waste oil is added into the reaction tank, alcoholysis and esterification can be carried out at the same time through the technology of slightly acidic catalyst, and the reaction speed is obviously accelerated. In addition, the key problem of high residual acid value in diesel oil production from waste animal and vegetable oil is solved by using metal salt treatment agent. These two key technologies can reduce the production cost of biodiesel and make biodiesel enter the production workshop from the laboratory. The biggest feature of this fuel is its good environmental protection. The tail gas emitted by diesel vehicles does not contain sulfur dioxide, and hydrocarbons and carbon monoxide are greatly reduced.
Disadvantages: Garbage oil is a kind of non-edible oil, with poor quality and extremely unsanitary, and its peroxide value, acid value and moisture content seriously exceed the standard. Containing toxins, flowing into rivers will cause eutrophication of water bodies. Once eaten, it will destroy white blood cells and digestive tract mucosa, cause food poisoning and even cause cancer. Frying oil, one of the "vegetable oils", is repeatedly used at high temperature for a long time, and comes into contact with oxygen in the air, resulting in complex reactions such as hydrolysis, oxidation, polymerization, etc., which increases the viscosity of the oil, deepens the color, increases the peroxide value, and produces some irritating substances such as volatiles, aldehydes, ketones and lactones, which have carcinogenic effects. Medical research shows that the toxicity of aflatoxin, the main hazard in waste oil, is 100 times that of arsenic.
First, so is the sewer. Gutter oil is the residue of domestic oil accumulated in sewers for many years. Nowadays, many black-hearted vendors go to places that use a lot of cooking oil, such as profit+black-hearted = gutter oil restaurants, and take out the oil that people washed into the sewers from their ditches, and then reuse it directly ... Especially in Shenzhen, roadside food stalls and breakfast vendors use gutter oil obviously. The most shocking thing is that a large chain restaurant "xx Frog" in Shenzhen has also discovered the use of swill oil, but now the Shenzhen Health Bureau has strictly controlled most regular businesses, but many roadside snacks are still very serious.
The reporter found in Building 2 of Cuizhu Community in Dalian Development Zone that there are many restaurants and many wells on the road in the community. The gutter oil fisherman skillfully fished one well after another at noon and then left quickly. Residents who see this situation should be righteous and prevent waste oil from flowing into market stalls. Hongmei Road, not far from here, becomes a snack street at night. It's hard to believe that maybe one of them used gutter oil.
Second, there is no obvious difference in color and taste between mixed gutter oil and general bulk edible oil.
Thirdly, according to the experimental determination, the rancidity index of "gutter oil" far exceeds the national regulations. If people take it for a long time, they will lose weight and suffer from developmental disorders, diarrhea and enteritis, as well as liver, heart and kidney enlargement and fatty liver. In addition, aflatoxin produced by gutter oil pollution is not only easy to cause liver cancer, but also can cause tumors in other parts, such as gastric adenocarcinoma, renal cancer, rectal cancer, breast cancer, ovary and small intestine.
[Edit this paragraph] China eats 3 million tons of waste oil every year.
10 meal, 1 meal will lead to gutter oil.
I don't know when it started, and urban sewers became a place where some people made a fortune. They fished out a lot of dim, turbid and reddish paste from there every day. These foul-smelling garbage can be turned into clear "edible oil" after only one night of filtration, heating, precipitation and separation, and finally returned to people's dining tables through low-price sales. This three-no product, called "waste oil", is still composed of triglycerides, but the toxic substances that cause disease and cancer are much more than the real edible oil.
"You must have eaten gutter oil, too." He Dongping, a professor at the School of Food Science and Engineering of Wuhan Institute of Technology, told the reporter. His other identity is the head of the Oil Working Group of the National Grain and Oil Standardization Committee. According to his estimation, at present, there are 2-3 million tons of waste oil returning to the table every year in China. In China, the total consumption of animal and vegetable oils in 1 year is about 22.5 million tons-that is to say, if you eat 10 meal, there may be 1 meal, which is gutter oil. So far, scientists have not found an ideal means to detect and identify gutter oil.
The oil dug out can earn 10 thousand a month.
Waste oil production has formed an industrial chain.
During the investigation, He Dong and his students learned that the cost of extracting 1 ton gutter oil from restaurant kitchen waste is about RMB in 300 yuan. Interest-driven is one of the main reasons for the long-term existence of waste oil. The people who dig gutter oil seem inconspicuous. In fact, they can earn an average of 70 to 80 yuan by digging a barrel of oil. A person can usually dig up four barrels a day. After recycling and refining, even if it is only sold at half the market price of edible oil, it can earn more than 1 10,000 yuan per month, which is equivalent to the income of senior white-collar workers. Students are told that even if they do odd jobs in this business, they can earn 2,500 yuan a month.
As a result, gutter oil has become a profiteering industry. Some people monopolize the kitchen waste of some restaurants and send people to buy it every day. A city is usually divided into several spheres of influence.
Jison, a student in He Dongping and head of the investigation team, said that waste oil was recycled wherever there was a catering industry. Conversely, because of the low price, these waste oils finally returned to the catering industry, from street shops to five-star hotels.
The results of medical research show that long-term intake of waste oil will cause obvious harm to human body, such as developmental disorder, enteritis, hepatomegaly, cardiomegaly and nephrosis, fatty liver and so on. Aflatoxin, one of the main hazards of gutter oil, is a strong carcinogen, and its toxicity is 100 times that of arsenic.
The utilization of waste oil is the responsibility of the government.
"People who engage in oil" all know a saying: "Oil mixed with oil makes the gods worry." In the view of researchers, the difficulty in the treatment of waste oil is that it is difficult to distinguish it from ordinary oil only in appearance and sense after washing, distillation, decoloration and deodorization. Illegal traders usually mix cooking oil with gutter oil, and if the content is small, it will be more difficult to detect.
Professor He Dongping has been engaged in the research of waste oil for 7 years. He and his research team are still undertaking the task of the National Standardization Administration Committee-"Research and formulation of the reuse standard of waste oil in urban kitchen waste". At present, the important task is to find an effective means to detect and identify waste oil.
As a researcher engaged in oil research, He Dongping always believes that the treatment of waste oil is not determined by testing methods or standards, but the key lies in government management.
He once calculated that 10000 people can produce 1 ton of kitchen waste every day, and these kitchen wastes can produce 130 kg of gutter oil after washing, distillation, decoloration and deodorization. When it returned to the market for sale, the price was half that of ordinary edible oil. Then the comprehensive statistical results show that the total profit of domestic gutter oil can reach 65.438+0.5 billion yuan to 2 billion yuan a year.
However, in the treatment of kitchen waste, China has been in an "anarchy" for a long time, which provides a large-scale "gray industry" space for some unscrupulous traders. Therefore, He Dongping's vision is that "kitchen waste must be centrally purchased and treated by the government, and gutter oil must be eliminated from the source". According to the scientist who has been engaged in cooking oil all his life, it may take about 10 years for China to completely ban cooking oil. [7]?
[Edit this paragraph] Identification of waste oil
Identification: Once "gutter oil" enters the market, consumers should learn sensory identification. According to experience, edible vegetable oil can be identified from five aspects: seeing, smelling, tasting, listening and asking on the road behind the hot pot in Cuizhu Mountain City, Dalian Development Zone.
Take a look. Look at the transparency, pure vegetable oil is transparent, and the transparency will be reduced due to the mixing of alkaline grease, wax and impurities in the production process; Look at the color, pure oil is colorless, in the production process, because the pigment in the oil dissolves in the oil, the oil will have color; Look at the sediment, its main component is impurities.
The second taste. Each oil has its own unique smell. You can put a drop or two of oil on your palm, rub your hands together and smell it carefully while it is hot. Odd oil indicates that there is a problem with the quality, and it is likely to be smelly waste oil; You can't buy it if it smells of mineral oil.
Three flavors. Take a drop of oil with chopsticks and taste it carefully. Oil with sour taste is unqualified, oil with bitter taste has been rancid, and oil with peculiar smell may be "gutter oil".
Listen 4: Take one or two drops of oil from the bottom of the reservoir, spread it on flammable paper, ignite it and listen to its sound. Products with normal combustion and no noise are qualified products; If the combustion is abnormal, it will make a "squeaky" sound, indicating that the water content exceeds the standard and it is an unqualified product; When burning, there is a "crackling" explosion, indicating that the water content of the oil is seriously exceeding the standard, which may be an adulterated product and must not be purchased.
Five questions: ask the merchants about the purchase channels, ask for the purchase invoices or check the sampling inspection report of the local food hygiene supervision department if necessary.
[Edit this paragraph] Rapid detection method of gutter oil
Fast and accurate detection method: The content of metal ions in oil can be judged by detecting the conductivity of oil by using the relationship between metal ion concentration and conductivity. Many experiments show that the conductivity of waste cooking oil is 5 to 7 times that of first-class edible oil, so it can accurately identify waste cooking oil.
[Edit this paragraph] The Office of the US Food and Drug Administration in the State Council issued an urgent notice.
In order to prevent waste oil from flowing into the catering service industry, the Office of the US Food and Drug Administration in the State Council issued the Emergency Notice on Preventing Waste Oil from Flowing into the Catering Service Industry on March 6, 2004 (No.20 20 10/0 of the Food and Drug Administration). The "Emergency Notice" pointed out: Recently, some media reported that criminals were processing "gutter oil". In order to prevent "gutter oil" from flowing into catering services and effectively protect consumers' food safety, please quickly organize supervision and inspection on the procurement and use of edible oil in catering service units, and strictly check the inspection records of catering service units and the implementation of the system of claiming certificates and tickets. At the same time, we must attach great importance to complaints and reports from the masses and verify clues in time. If it is found that the source of edible oil purchased by catering service units is unknown, or "gutter oil" is purchased and used, it is necessary to supervise the catering service units to immediately stop using and destroy it, and at the same time severely investigate and deal with it according to law. If the circumstances are serious, the license shall be revoked. The urgent notice also requires the health departments (bureaus) of all provinces, autonomous regions and municipalities directly under the Central Government and the Food and Drug Administration to report the supervision and inspection to the Food Safety Supervision Department of the US Food and Drug Administration before the end of April.