Yes, you can. It's simple. Just pour cooking oil into the pot, heat it, peel a garlic and put it in the pot. After a period of time, if garlic turns red, it means that there is an aflatoxin, which can be judged as gutter oil; If garlic does not turn red, it is safe and safe to eat. Although this judgment method is simple, there is no evidence to prove its scientificity.

Waste oil does not necessarily refer to the oil fished out of the gutter. Oils from many sources, such as repeated use and extracted from leftovers, are collectively called "gutter oil". Because gutter oil is used repeatedly, it accumulates a lot of harmful substances, and the content of trans fatty acids is increasing, which will do great harm to our health after eating. Here are several methods to identify the quality of edible oil.

Transparency. Normal cooking oil is transparent in color, while gutter oil contains a lot of chemical elements because of repeated use and special treatment, so the color is turbid and the transparency is extremely low, and even sediment can be seen at the bottom of the oil bottle.

Temperature. Normal edible oil is made of peanuts, soybeans, rapeseed and other crops, which tastes delicious. The smell of gutter oil will be a little sour, which is caused by the chemical elements contained in it.

Taste. By comparing some tastes, we can also judge the quality of edible oil. The method is to pick a drop of oil in your hand with chopsticks, rub it gently and lick it with your tongue. Oil is normal if it tastes slightly fragrant. If it tastes slightly sour or bitter, it is most likely gutter oil.

High temperature test. Pour the oil into the pot and turn on the fire. After a period of time, if the color of the oil becomes thick and black, it is most likely gutter oil, because it contains small particles, which will burn and change color after high temperature. A spoonful of oil destroys the health of the whole family. Everyone makes such mistakes when eating oil.