The so-called saliva oil means that the hotel staff will recycle the leftovers left by the guests and skim off the oil in the leftovers, which is named after it is mixed with the saliva of the guests. In this incident, the old Tangke hotpot restaurant used this kind of repeatedly used saliva oil. First, the nutrients in food, such as vitamins, amino acids and fatty acids, are destroyed, which reduces the nutritional value and thus destroys the nutritional system in the human body.

Second, promote the chemical reaction between ingredients in food, leading to premature aging symptoms, such as accelerated skin aging.

Third, it leads to and aggravates the occurrence of some chronic diseases such as hypertension, hyperlipidemia, gallstones, diabetes and gout.

Fourth, after repeated high-temperature cooking, saliva oil is easy to produce a carcinogen "heterocyclic amine", which will cause cancer in the human body. Consumers can generally identify "saliva oil" by looking, smelling, tasting, listening and asking.

Transparency at first glance, pure vegetable oil is transparent, and "saliva oil" is colored, with sediments and impurities.

Second, drop a drop or two of oil on the palm of your hand, rub your hands together, and smell it while it is hot. It is likely to be "saliva oil" with peculiar smell.

The third taste, take a drop of oil with chopsticks, which is sour or bitter, indicating that it has become sour and corrupt, and may be "saliva oil".

Listen, take a drop or two of oil from the bottom of the reservoir and coat it on flammable paper. Abnormal combustion and "click" explosion indicate that the water content of oil is seriously out of standard and the quality is problematic.