At present, two to three million tons of “gutter oil” are returned to the table every year. The country’s annual consumption of cooking oil is about 22.5 million tons – that is to say, on average, for every 10 meals, 1 of them touches gutter oil. The scientific name of “gutter oil” is waste edible grease, which is the catering industry and instrument processing industry in the process of business, the production of inedible animal and vegetable fats and oils, including frying old oil, hot pot oil slop oil and edible grease wastewater by the oil-water separator or grease trap separation after the production of inedible grease. Generally speaking, gutter oil can be divided into the following categories: First, the narrow sense of gutter oil, that is, the greasy floating in the sewers or hotels, restaurants, leftovers, leftovers (commonly known as slop) after simple processing, refining oil; Second, poor quality pork, pig offal, pig skin processing and refining the output of oil; Third, the oil used for frying food more than the number of times required gutter oil, and then be reused or to which Add some new oil after the re-use of oil. The dangers of gutter oil: Gutter oil is a non-edible oil of extremely poor quality and unhygienic, with peroxide value, acidity and moisture seriously exceeding the standard. It contains toxins and can cause water nutrients in rivers, and once consumed, it can damage white blood cells and digestive tract mucosa, causing food poisoning and even cancer. The gutter oil refined from “slop oil” contains aflatoxin, which is 100 times more toxic than arsenic. Long-term intake, people will experience weight loss and developmental disorders, diarrhea and enteritis, as well as liver, heart and kidney enlargement and fatty liver lesions. In addition, the toxicity of aflatoxin from contaminated gutter oil not only makes people susceptible to liver cancer, but also tumors in other parts of the body, such as cancer of the stomach, kidney, rectum and breast, ovary, small intestine and other parts of the body. Therefore, for the sake of our own health and the health of future generations, our society needs to pay as much attention to gutter oil as it does to melamine. How to identify gutter oil? One look. Look at the transparency, pure vegetable oil is transparent, in the production process due to the mixing of alkali fat, wax, impurities and other things, transparency will decline; look at the color, pure oil is colorless, in the production process due to the pigment in the oil dissolved in the oil, the oil will be colored; look at the precipitate, its main component is impurities. Second smell. Each kind of oil has its own unique smell. You can put a drop or two of oil on the palm of your hand, rub your hands together, and smell its smell carefully when it is hot. There is an odor of oil, indicating that the quality of the problem, there is a bad smell is likely to be gutter oil; if the smell of mineral oil can not buy. Three taste. Take a drop of oil with chopsticks and taste it carefully. Taste with sour oil is substandard products, there is a burnt bitter taste of the oil has been rancid, there is a strange smell of oil may be gutter oil. Four listen: take one or two drops of oil from the bottom of the oil layer, apply it to a flammable piece of paper, ignite it and listen to the sound. Burning normal no sound is qualified products; burning abnormal and “squeaking” sound, moisture exceeds the standard, is not qualified products; burning “crackling” explosion, indicating that the water content of the oil seriously exceeds the standard, and may be adulterated products, absolutely not purchase. Five questions: ask the merchant’s purchase channel, if necessary, ask for the purchase invoice or check the local food hygiene supervision department sampling test report.