Safety of edible oil： Don’t mix old oil with new oil. Clean the oil pot thoroughly every 3 months.

　　Beijing, June 22 (Xinhua) According to the voice of the economy "Daily 315", I believe that many consumers believe that compared with vegetables and fruits, edible oil is a kind of food that can withstand storage. Is this really the case? Yi Zhu, an associate professor at the College of Food Science and Nutritional Engineering of China Agricultural University, and Dr. Kai Zhong, an associate researcher at the National Center for Food Safety Risk Assessment, were guest programs to pay attention to the topic of food nutrition and safety in life.

　　Voice of the Economy: In life, many families use oil pots. When they see that the oil in them is running out, they just pour in new ones. Is it scientific to mix new oil with old oil?

　　Yi Zhu: This is definitely unscientific. Don’t mix new oil with old oil. When the old oil is used up, put new oil into the oil pot, otherwise the oxidation speed of oil will be accelerated, and the oxidation of oil will be contagious. Generally speaking, it is enough to add the amount needed by a family for a week to the oil pot, and the oil pot should be thoroughly cleaned every three months or so.

　　You’d better buy a glass oil pot, not a plastic one, and you’d better buy a small package when you buy cooking oil, which is healthier. After the oil in plastic bottles is bought back, it should be packed into dark glass bottles or ceramic cans as soon as possible. Because the rancidity speed of oil is directly related to light, it should be protected from light.

　　Voice of the Economy: We usually say that oil will smell old when it is put on for a long time, which will affect the taste. Is this harmful to health?

　　Kai Zhong: Actually, the sulfuric acid produced by oleic acid spoilage is mainly bad for people’s senses. Some oil with severe rancidity may cause some acute gastrointestinal irritation, but basically we don’t eat this oil, because the taste is already very strong.

　　Voice of the Economy: Some people may not be willing to give up the oil left after frying food. Next time, they will use this oil for cooking. Does the oil used twice have an impact on health?

　　Kai Zhong: Repeatedly fried oil is not good.

　　Yi Zhu: Frying oil at high temperature will produce some small molecules, which may lead to human aging, so we must use less oil when using oil and control the oil temperature.

　　Voice of the Economy: Generally speaking, how often is it healthy to clean the oil pot thoroughly?

　　Yi Zhu: Clean it thoroughly every three months or so. The oil pot must be made of glass.