In the process of improving living standards, people are putting more effort into improving the quality of life and inventing more convenient items. One of these inventions is the refrigerator. A refrigerator is a device that keeps food or other items cold and contains a compressor and an ice maker for freezing. It is a storage box with a cooling device.
A refrigerator is an essential item in people's daily lives. In people's minds, a refrigerator can both refrigerate and preserve food. Whether it's chicken, duck, fish, meat, fruits, vegetables, cooked or raw, fresh or not, people just throw them into the refrigerator thinking it's "safe". However, a refrigerator is not a "safe".
A refrigerator can only preserve food for a short period of time and does not effectively inhibit the loss of nutrients in food.
The principle behind the preservation of food in a refrigerator is that the metabolism of all microorganisms requires the catalysis of enzymes, and the rate of enzymatic reactions depends on temperature. For every 10 degrees Celsius decrease in temperature, the reaction rate decreases by half, and the metabolic rate also decreases, thus keeping the food fresh.
However, even though low temperatures can reduce the rate of all chemical reactions in food and extend the time required for microorganisms to reproduce, it cannot completely stop chemical reactions or eliminate all microorganisms in the food. The freshness of the food will still slowly change. For example, psychrophilic bacteria can grow at temperatures of 50℃ or lower, and psychrotrophic bacteria can reproduce at temperatures of 40℃ to 70℃.
There was an experiment conducted where fresh fish and meat were stored at -18℃ for a total of 8 months. It was found that after the third month, there was a significant change in the nutritional content of the fish and meat, mainly in vitamins A and E, with a loss of about 20% to 30%. By the eighth month, the loss was even greater. In addition, the hemoglobin in the fish and meat oxidized significantly, not only causing the color to fade, but also resulting in a significant loss of moisture.
Typically, the temperature in the freezer compartment of a household refrigerator is generally around -18℃, and at this temperature, the preservation of the flavor, nutrients, and freshness of food can only be effective within a certain time range. After this period of time, it does not have much impact on the rate of change in the nutrients and flavor of the food, and cannot prevent the gradual loss of nutrients and slow deterioration of quality.
Therefore, it is best not to freeze fish and meat in the refrigerator for more than two months. If food is stored in the refrigerator for too long, it will not be able to enjoy the original taste and nutrition when consumed. Some people may think that nutrient loss or damage doesn't matter as long as they can eat. In fact, long-term frozen food is not just about losing nutrients. The longer meat is frozen in the refrigerator, the greater the possibility of fat oxidation, and the oxidation process can produce mild oxidants and carbonyl compounds, both of which are harmful to the body. If you find that the fat in the meat has turned yellow, it means that it has been oxidized and is already dangerous and harmful to the human body, which means it is best not to eat that piece of meat.
After storing things in the refrigerator, some people may forget what they have stored in the freezer compartment due to busy work or heavy household chores, especially when food becomes less discernible after freezing. To avoid this situation, a small label can be attached to the outer packaging bag with the content and date written on it, and then placed in the freezer compartment. Alternatively, a "Frozen Food Storage Checklist" can be created and posted on the door of the freezer compartment to keep track of what is stored in the freezer and easily retrieve items when needed. Additionally, it is important to minimize the frequency of taking frozen food out of the refrigerator and avoid thawing and refreezing. Frequent freezing and thawing is not conducive to food preservation.
Frequent thawing causes significant damage to meat. Each time meat is thawed, a lot of nutrients are lost, and it affects the taste and freshness when consumed. Therefore, meat cannot be repeatedly frozen. After buying meat, it can be cut into small pieces according to the amount needed for each meal, then wrapped in plastic bags and stored in the freezer compartment. One piece can be taken out for each meal.
For vegetables, people usually determine whether they can be eaten based on their appearance. As long as the color is still fresh green, they are considered edible. However, when vegetables are stored at temperatures between 0℃ and 4℃ for 3 days in the refrigerator, even if there is no significant change in appearance, it is best not to eat them as the nutritional content has been greatly reduced.
Leafy green vegetables, which are rich in nutrients, should not be stored in the refrigerator for more than 3 days. If stored for a long time, degradation of vitamins will occur and their content will decrease significantly. For example, vitamin C and carotenoids decrease, and eventually vitamin C completely disappears. At the same time, the concentration of harmful nitrite will increase from a very low level to a high level, and it will react with proteins and amines in the stomach to form nitrosamines. Nitrosamines are carcinogens and are closely related to the occurrence of gastric cancer.
Some vegetables contain harmful bacteria. For example, celery and small red radishes contain a type of bacteria called enterobacter. This bacteria is very suitable for growth in a temperature range of 0℃ to 4℃. The longer it is stored in the refrigerator, the more it will reproduce. Eating such vegetables can easily cause gastrointestinal infections, which can harm human health.
During the refrigeration process, vegetables, especially those like tomatoes, cucumbers, and watermelons that are intended to be eaten raw, should be wrapped in a plastic bag before being refrigerated. This is because the refrigerator is not a sterilizer, and various microorganisms can grow and reproduce in a moist environment.
The refrigerator should be cleaned regularly to maintain the hygiene of the food inside. Before cleaning the refrigerator, it should be unplugged and the power supply should be disconnected. Take out the food in the refrigerator. It is best to clean the exterior of the refrigerator every day, using a slightly damp soft cloth to wipe the exterior and handles of the refrigerator.
Dip the soft cloth in clean water or dishwashing liquid, gently scrub, and then dip in clean water to remove the dishwashing liquid. Remove the accessories inside the refrigerator and wash them with clean water or dishwashing liquid. When cleaning the "switch", "light bulb", and "thermostat" of the refrigerator, wring the cloth or sponge drier. After cleaning the interior walls, use a soft cloth dipped in glycerin (medical enema) to wipe the interior walls. It will be easier to clean the next time. Use a cloth soaked in alcohol to clean and wipe the sealing strip. If alcohol is not available, use a 1:1 vinegar-water mixture to wipe the sealing strip. It has a good disinfection effect. Use a vacuum cleaner or a soft brush to clean the ventilation grille at the back of the refrigerator. Do not use a damp cloth to avoid rusting. After cleaning, plug in the power supply and check if the temperature controller is set to the correct position.
In addition, there is a misconception about antibacterial refrigerators, that is, using an antibacterial refrigerator means that food will never spoil again. In fact, antibacterial refrigerators mainly add special antibacterial agents in the materials of certain parts of the refrigerator, which can inhibit the growth of bacteria on the surfaces of the refrigerator walls, door handles, etc., but cannot inhibit the growth of bacteria inside the food.
As a necessary appliance in households, refrigerators consume a large amount of electricity every day. Whether from the perspective of energy conservation or expense reduction, it is important to have some energy-saving tips for refrigerators to reduce energy consumption. Here are 6 tips for refrigerator energy saving:
1. Minimize the number of times and duration of opening the refrigerator door when accessing food. Before taking something out, think about what you need and try to get everything at once. Opening the door releases cold air and the compressor needs to run for tens of minutes to restore the refrigeration temperature, which consumes more electricity.
2. If you want to store fruits, vegetables, or other high-moisture foods, wash and dry them before putting them in the refrigerator. Excess moisture can cause thick frost and shorten defrosting time, saving energy.
3. When putting food with a temperature higher than room temperature into the refrigerator, let it cool down before putting it in. Food with a higher temperature than the room will increase the refrigerator temperature rapidly, resulting in thicker frost on the evaporator surface and longer working time for the compressor, increasing power consumption.
4. In hot summer weather, making ice and cold drinks in the refrigerator should be done at night. The lower temperature at night facilitates the heat dissipation of the condenser. Moreover, there are fewer openings of the refrigerator door at night, and the compressor works for a shorter time, saving energy.
5. Refrigerators should be placed in a location with lower temperature and good ventilation, away from heat sources and direct sunlight. When placing the refrigerator, leave appropriate space on the top, sides, and back to facilitate heat dissipation.
6. Raw and cooked food should be stored separately in the refrigerator. It is best to wrap them in plastic bags or put them in sealed containers to prevent cross-contamination and water loss. Fresh food should be consumed as much as possible to reduce the chance, quantity, and time of food storage in the refrigerator.
It is important to leave appropriate space between the food stored in the refrigerator to maintain air circulation. Hot food should be cooled to room temperature before putting it in the refrigerator to avoid continuous operation. Food intended to be stored in the refrigerator should be wrapped in plastic bags or cling film or placed in sealed containers to prevent moisture loss, shrinkage, or flavor mixing. Food with water content should be removed before being placed in the refrigerator to prevent excessive frost formation due to water evaporation. Additionally, regular checks should be made to ensure the quality of the food stored in the refrigerator. If any signs of spoilage are found, they should be removed immediately. Regular cleaning of the refrigerator, defrosting, removing ice, and removing odors are also necessary.
