Does heating food in a microwave oven cause cancer?

　　Question: Can microwaved food cause cancer?

　　[Response] Microwave heating is physical heating, does not change the molecular structure, and is harmless to the human body under normal use.

　　According to experts, microwave heating is a heating method that relies on objects to absorb microwaves and convert them into heat energy. Food contains a certain amount of water. When microwaves radiate to the food, the water molecules produce microscopic molecular motion with the microwave field, resulting in a phenomenon similar to friction, which increases the temperature of the water and the temperature of the food. In other words, no chemical changes occur in the food when heated by microwaves.

　　Zhang Zhaobo, an expert in microwave power application and measurement technology in my country and a professor at the University of Electronic Science and Technology of China, said that food is mostly composed of fat, protein, vitamins and other substances. After absorbing microwave energy, the water in the food will rotate at high speed and vibrate, causing friction with each other to generate heat. The microwaves emitted by current microwave ovens are generally 2.45GHz, which means that the molecules in the food vibrate 2.45 billion times per second, generating enough heat in a short period of time, but their energy is far from enough to change the chemical bonds of the molecules. “This is purely physical heating and does not cause any change in molecular structure. How can it produce carcinogens? ”Zhang Zhaobo said that the microwave oven was invented in the United States in 1947, and there have been no epidemiological reports of cancer caused by microwaved food.

　　Fan Zhihong, associate professor at the School of Food, China Agricultural University, told reporters: "Microwaves only heat water molecules in food. The food does not undergo chemical changes and does not produce carcinogens. ”

　　But she said that if food is heated to too high a temperature, whether it is microwave heating or traditional methods, carcinogens may be produced. Heating food to a temperature exceeding 120°C, such as when we are frying French fries, potato chips and baking biscuits, snacks, etc. coffee When eating beans and other foods, the reaction between amino acids and carbohydrates may produce acrylamide, a suspected carcinogen.； Above 200°C, for example when frying and cooking fish, the protein may produce heterocyclic amine carcinogens ； When the temperature exceeds 300°C, such as when kebabs, barbecues, or meat are improperly cooked and burnt, the fat in the food will produce a large amount of benzopyrene carcinogens.

　　Will microwave heating produce such high temperatures? Fan Zhihong said that the microwave oven mainly heats the water in the food. As long as it is used normally and the water is not evaporated, the temperature of the food will be lower than 100°C and no carcinogens will be produced.