Heating food in a microwave oven is very safe, killing bacteria and viruses in the food and retaining more nutrients in the food. As for the human body, as long as it is used properly, it will not be harmful. Because the design of the microwave oven meets strict safety standards, its radiation, than cell phones and computer monitors are smaller. However, the following categories of food can not be heated with a microwave oven 1, avoid heating meat to half-cooked and then microwave heating: because in the half-cooked food bacteria will still grow, the second time and then microwave heating, due to the short time, it is not possible to kill all the bacteria. Frozen meat should be thawed in the microwave oven first, and then heated for cooked food. 2, avoid refreezing the meat thawed by the microwave oven: because the meat thawed in the microwave oven, in fact, has been a layer of low-temperature heating outside, the bacteria can be reproduced at this temperature, although the refreezing can be made to reproduce to stop, but can not be killed by the live bacteria. Has been thawed with the microwave oven meat, if then put into the refrigerator frozen, must be heated to fully cooked. 3, avoid deep-fried food: because of the high temperature oil will splash lead to fire. If inadvertently caused by the stove fire, do not open the door, but should first turn off the power, to be extinguished after the fire and then open the door to cool down. 4, avoid overtime heating: food into the microwave oven defrosting or heating, if you forget to take out, if the time is more than 2 hours, it should be thrown away do not want to avoid food poisoning. 5, avoid using ordinary plastic containers: the use of special microwave oven utensils to contain food into the microwave oven to heat up, a hot food will make the plastic containers deformed, and secondly, ordinary plastics will release toxic substances, contamination of food, endangering human health. 6, Avoid using metal utensils: because the furnace into the iron, aluminum, stainless steel, enamel and other utensils, the microwave oven in the heating will produce sparks and reflect microwaves, both damage to the furnace body and heating food is not cooked. 7, avoid the use of closed containers: heating liquids should be used in a wide-mouth containers, because in closed containers of heat generated by the heating of food is not easy to disseminate the heat, so that the pressure inside the container is too high, prone to cause blasting accidents. Even when frying shelled food, but also to use a needle or chopsticks beforehand to puncture the shell, so as to avoid heating caused by bursting, splashing dirty walls, or splash injuries.8, avoid the microwave oven in the bedroom: at the same time, should pay attention to not cover the microwave oven on the radiator grille with items.9, avoid working for a long time in front of microwave ovens: turn on the microwave oven, the person should be away from the microwave oven or the person away from the microwave oven is at least 1 meter away.