Hong Meiying, deputy executive director of Taiwan Province Excellent Agricultural Products Development Association, shared that the shelf life of food stored in18 C cabinet is calculated by "hours", so we should pay more attention to the eating time when purchasing. In particular, conditioned food will form an environment suitable for bacterial growth after heating. For example, E.coli can divide and reproduce every 20 minutes in a suitable growth environment. Based on this calculation, under the best conditions, 1 cell can reproduce to more than 2 million after 8 hours, and 10 million after 0 hours, especially at room temperature or even in hot summer, which is a good temperature layer for bacterial growth, so it is very important to eat it as soon as possible after heating.
As for the frozen prepared food, it must be placed at-18℃ to maintain good flavor and quality, so when buying, you can pay attention to whether the temperature displayed on the freezer is really controlled at-18℃. In addition, the frozen food in the freezer should be neatly stacked, not exceeding the "load line", generally about seven minutes full, and you must reserve space for cold air circulation. When you take it, you must also pay attention to whether the frozen state of the food itself is still as hard as a stone. If you press it with your fingers, you find that the food in the package has become soft or the appearance is wet, which means that the food has begun to thaw and the quality will be greatly reduced. Finally, don't forget to pay attention to whether there is a layer of frost on the surface of food packaging. If there is frost, it means that the product may go through the situation of heating up and then cooling down, and it is easy to deteriorate.
After buying the prepared food, the next step is of course to heat it up and enjoy it! Hong Meiying also reminded that the heating methods and conditions on the packaging must be carefully read before microwave reheating, because there are many changes in the packaging materials of prepared foods, some of which can be directly heated, and some must be partially packaged or punched, all based on the uniform heating of ingredients or the different properties of packaging materials, so it is very important to heat according to the instructions.
What should I pay attention to when buying home? How to keep the temperature and microwave is the most critical. Then, what should you pay attention to if you buy chilled or frozen prepared food in the store and take it home instead of reheating it in the microwave oven? Chen Huihuang said that the most easily overlooked link in the cold chain, besides the logistics from the factory to the place of sale, is the process that consumers buy their own homes. Because the manufacturer's distribution logistics system has been controlled, Jinkouxiang Conditioning Food Co., Ltd., which has assisted many convenience stores in OEM, said that its refrigerated conditioned food will not only be distributed by self-built low-temperature logistics fleet, but also undergo various strict tests to ensure that the microbial detection of the goods is completely qualified within 4 days after they arrive at the store, and the distribution logistics control will be implemented.
However, it is still difficult for consumers to control the whole process from factory to access. If consumers don't eat on the spot after buying, they often forget to keep the food warm after leaving the refrigerator or freezer, especially when the shopping bag is placed in the trunk of the car. Therefore, Chen Huihuang suggested that if you don't eat cooked food heated by microwave oven immediately, you should try to buy it at the last stage of shopping, pack it in an ice pack and put it in the refrigerator immediately after you get home. (Recommended reading: there is a set of refrigerator storage, grasp the first-in, first-out, cooked! )
But when I bought my own microwave oven, I encountered another problem: the power of domestic microwave oven is different from that of supermarket microwave oven. What should I do? At present, the power of microwave ovens in supermarkets is generally 1400W, while the power of domestic microwave ovens is between 700-900 W ... Chen Huihuang said that the suggestions on packaging can be used as a reference when using microwave ovens. Basically, the power of the microwave oven at home is halved, and the time is doubled. However, it should be noted that some household microwave ovens have consumption and output power, which should be converted by output power; In addition, considering the size of your microwave oven, a larger microwave oven needs more time, because the microwave heating effect decreases with the square of the distance.
He mentioned that in fact, the best method is "gradual heating", and phased microwave heating is the best, because if the microwave is not enough, you can do it again, but it will not be saved if it is overheated and burnt, and it will not produce toxic substances because of overheating. Wu, chairman of Jinkouxiang Company, also shared a trick. In fact, you should avoid tearing only one corner of the sealing film to heat the food, because it will make the food heated unevenly, the temperature near the opening is particularly high, and the diagonal opening is not hot enough. Therefore, he suggested that as long as a small hole is punched in the middle of the sealing film, the heat energy can be better circulated during microwave, and the product is heated more evenly and has a good flavor.
In fact, cooked food is getting more and more intimate now. Some packages will not only indicate how to heat in the supermarket microwave oven, but also include the microwave time suggested by the household microwave oven, and even suggest how to heat if there are ovens, rice cookers and other equipment. You may wish to refer to it when you buy it next time. You may find that the cooked food tastes different.
Is it unhealthy to prepare food? A balanced diet is the key. Many people think that cooked food has no nutritional value and it is unhealthy to eat too much. However, Chen, an associate professor in the Department of Food Science at Fu Jen Catholic University, said that in fact, unless there is an extreme cooking process or excessive salt is added, the nutrients in the prepared food are just like those eaten outside. If you are worried that microwave will affect food and cause nutrient loss, in fact, according to the suggested heating method, there is no problem at all. The principle of microwave oven is to convert electric energy into microwave energy and emit it, and heat food by rubbing water molecules in food. In fact, it is just a process of "reheating". Some studies even pointed out that microwave ovens can retain nutrients better than boiled water, because water-soluble nutrients (such as vitamin C) can retain more.
Some people think that supermarket lunches can be preserved for so long without preservatives. Chen Huihuang explained that in fact, as long as the environment is protected and the temperature is properly controlled, there is no need to add preservatives to the prepared food. Other myths about microwave ovens include whether they will explode if they are not torn open. Chen told me that he must be careful. If the water vapor in the package does explode after accumulating to a certain limit, it is best to tear the outer package before microwave. As for whether microwave is the last resort of sterilization? Chen believes that microwave can actually sterilize, but the general method of microwave conditioning food is "reheating" to make the food reach a palatable temperature. In fact, the temperature is not high enough to be sterilized. Recommended reading: Is it right to heat leftovers in the microwave oven? Master the five principles of health)
Finally, the choice of cooked food is mostly for convenience, but with the rise of health awareness, foodies are also very concerned about how to eat healthily. So how to eat? Zhang Yue, a nutritionist of Food Power, commented that the biggest problem in preparing meals in supermarkets is the insufficient quantity of vegetables. Buying lettuce salad and mixing lettuce directly into the lunch box is also an option. Or the supermarket will sell fruit, so buy a pack to supplement water-soluble fiber, vitamins and minerals. Nuts are also available in the snack area. It is best to choose nuts baked at low temperature without seasoning. You might as well bring some when you buy dinner. They will be the best snack choice between meals.