There are many catering industries that use old oil illegally. Although some catering industries have stated that old oil is a traditional production process, in fact, eating old oil is a great harm to the human body.

National level 2 public nutritionist Gong Hongbin said, first of all, the old oil hygiene standards will not pass, quality can not be guaranteed. Second, because of the high moisture content of the old oil and the presence of food residues, it can easily lead to rancidity of the oil, resulting in a series of corresponding harmful products. In addition, the old oil after repeated high temperature treatment can cause the deterioration of fats and oils, produce substances harmful to the human body, it will be toxic to the human liver, reproductive organs, and even carcinogenic effects.

So how do you tell the old oil? Gong Hongbin introduced, generally through the look, smell, listen to identify. A look : The chopsticks will be stained with grease when they are served. If the oil is in a liquid state, it means that the oil is normal. Conversely, if the oil solidifies within a few seconds, the oil is not good. At the same time, it depends on transparency. The pure vegetable oil is transparent, and the “old oil” is dark in colour with precipitates and impurities. Two news: The normal scent needs to be heated for a certain period of time before it is emitted. If the hot pot or dish just comes out with a strong non-greasy fragrance, you need to be vigilant. Listening: Take one or two drops of oil at the bottom of the oil layer and coat it on flammable paper. The combustion is abnormal and a “bang” sound is emitted, indicating that the water content of the oil is seriously excessive and the quality is problematic.