Microwave ovens have become one of the common electrical appliances in the home and are widely used for heating and reheating food. However, some consumers are concerned that using microwave ovens can cause changes in the nutrient content of food and may not be safe. So, are there scientific basis for these concerns? What scientific understanding can help consumers use microwave ovens correctly?
First, let's take a look at the principle of heating food in the microwave. A microwave is an electromagnetic wave with a frequency of 300 megahertz to 300 gigahertz and a wavelength of 1 millimeter to 1 meter. The microwave frequency is higher than radio waves, lower than infrared, visible light and ultraviolet rays, and is a non-ionizing radiation electromagnetic wave.
Microwave ovens are electrical appliances that use electromagnetic waves in this microwave frequency band to heat materials. When the food absorbs microwaves, the electromagnetic energy is converted into heat energy, and through the rotation of the agitator and the reflection of the inner wall of the furnace, the food can be efficiently heated from all directions. Different from traditional heating methods such as cooking and frying, microwave heating does not need to rely on heat transfer medium, heat transfer will not be lost, and the inside and outside of food can be heated at the same time, so that the heating speed is faster, more efficient, and the thermal inertia is smaller.
So, what are the effects of microwave ovens on human health? A large number of scientific experiments have proved that as long as you buy a regular microwave oven that meets national standards and operate it correctly, it is safe and will not have any impact on human health.
First of all, we can rest assured about the concern of "microwave radiation". Unlike X-rays or γ-rays, microwaves are non-ionizing radiation electromagnetic waves with frequencies and wavelengths similar to the radio waves we are exposed to in our daily lives (such as radio, television, navigation, etc.). The energy of microwave photons is very weak, much lower than the energy of weak interactions between molecules, so microwave radiation cannot destroy molecular structure or covalent bonds, will not damage the structure of matter, and we do not have to worry about the risk of microwave radiation at all.
Secondly, we can also rest assured about the concern of "microwave leakage". Regular microwave ovens are designed and produced with metal walls and metal meshes, which can limit microwaves to the cavity of the microwave oven and avoid microwave leakage. Therefore, microwave ovens that meet national standards are safe and we can use them with confidence.
There is also a concern that microwave food is harmful. In fact, whether it is the traditional cooking method or the microwave heating method, when the food is overheated or heated for too long, it may produce substances that are not good for health. Compared with other heating methods, the advantage of microwave heating is that it can increase the heating rate and shorten the heating time, which is conducive to retaining nutrients in food.
So, what should we pay attention to when using a microwave oven?
First of all, before using the microwave oven, we should read the instruction manual in detail and use the microwave oven correctly and standardized.
Secondly, the choice of food also needs to be particular. Nuts with skin or shells, eggs with eggshells, foods in closed packaging, etc. cannot be heated or cooked directly in the microwave. The inside of these foods expands faster when heated than the outside, and when heated, a large amount of water vapor that cannot be released will be generated, causing high pressure, which in turn causes the food to explode. In addition, foods of similar shape, such as grapes and cherry tomatoes, which contain high moisture and are not suitable for heating in the microwave, because they are prone to plasma flames under microwave fields, which may cause fires.
The choice of container also requires caution. The container placed in the microwave oven should be a plastic container specially designed for use in the microwave oven, or a glass and ceramic container without a metallic pattern. Any packaging containers or cutlery containing metal should not be heated in the microwave, including tin foil, aluminum foil, etc. Because microwaves will be reflected when they encounter metal, it is easy to cause microwave source breakdown and even cause explosion. In addition, we should also avoid using completely closed containers, as heat is not easily released during heating, which may lead to excessive internal pressure and the risk of bursting burns.
Finally, the heating operation should be standardized. According to the type and state of food, reasonably choose the heating time and microwave fire, and it is not advisable to use high power for long-term overheating. If we are not sure how much power to use and how long to heat, we can give preference to low power for short periods of time. In addition, it is not advisable to heat liquid food to a boiling state for a long time to avoid boiling and splashing. Special attention should also be paid to the strict prohibition of idling the microwave oven to avoid fire or even explosion.
In general, scientific experiments have proved that the use of qualified microwave ovens after correct operation and purchase is safe and will not have any impact on human health. We only need to follow some precautions to make proper and scientific use of microwave ovens to facilitate our lives.