Everyone likes to keep food fresh in the refrigerator. Not all foods can be put in the refrigerator, especially the following common foods. After tomatoes are frozen at low temperature, the flesh of tomatoes is blistered, soft and rotten, or cracked, with black spots on the surface, immature and tasteless, and even rotten in severe cases. Bananas will turn black and rot when stored below 12℃. Fresh Litchi If Litchi is left at 0℃ for one day, the skin will turn black and the pulp will go bad. After the chocolate is put into the refrigerator, once it is taken out, it will form a layer of frost on the surface at room temperature, which is easy to go moldy and deteriorate and lose its original flavor. Ham If ham is kept in the refrigerator at low temperature, the water in it will freeze, the fat will precipitate, the ham meat will agglomerate or loosen, and the meat will become stale and perishable. Bread: In the baking process, the linear segment of starch in flour has aged, which is the reason why bread has elastic and soft structure. With the extension of storage time, the linear part of amylopectin in bread slowly associates, which makes the soft bread gradually harden. This phenomenon is called "aging". The speed of "aging" is related to temperature. At low temperature (above freezing point), bread will age faster, but after being put in the refrigerator, the degree of hardening will come faster. Cucumber and green pepper: Cucumber and green pepper will freeze and "hurt" if put in the refrigerator for a long time-turn black, soften and taste bad. Cucumbers also have sticky hairs. Because the temperature of refrigerator storage is generally around 4℃ to 6℃, the suitable storage temperature of cucumber is 10℃ to 12℃, and the suitable storage temperature of green pepper is 7℃ to 8℃. So it shouldn't last long. In the era when there is no refrigerator, in order to prolong the storage time of food, people often seal the food after cooking at high temperature. (Why is this? Please explain the following phenomenon! First of all, high-temperature cooking can kill most bacteria and other organic substances in food, so that food loses the source of deterioration (corruption). Then sealed, so that external bacteria can not enter, so as to achieve the purpose of long-term preservation of food without deterioration. Similar methods include pickling and drying. It is also to create an environment in which bacteria cannot reproduce, so that food will not go bad. Pickling is to make the salt content of food reach a high concentration, so that cells can't absorb nutrients and water and can't survive (this can refer to the osmotic principle of cell membrane). Like salted fish and pickles. Drying is mostly used for pasta, which makes food lack the water needed for bacterial reproduction. Of course, this method is only applicable to air-dried areas, such as Ciba in Xinjiang, fried noodles with dry food in the north and so on. Eggs: After fresh eggs are put for a period of time, the yolk tends to stick to the shell or turn yellow. This is because, after a long time, mucin in protein will be slowly diluted under the action of protease, losing the function of fixing egg yolk. If the egg head is placed upright, there is an air chamber in the egg head, and the gas inside will make the yolk unable to get close to the eggshell. Vegetables: remove the rotten parts of vegetables, put them in plastic bags, tie the bags tightly and put them in a cool and dry place. This method is very effective in preserving cucumbers, bell peppers, lettuce, small green peppers, coriander and immature tomatoes. Overnight bread: wrap the bread in the original packaging wax paper, then wrap it in a few pieces of wet paper soaked in cold water, put it in a plastic bag and tie the bag tightly; Or put a fresh celery in a plastic bag full of bread to keep the bread fresh. 1 Clean the refrigerator. Before you go to the mall to buy a lot of food, you should throw away all the food in the refrigerator that will expire or look or smell suspicious. Wash the food cabinet with hot soapy water and dry it; Adjust the temperature in the refrigerator (freezing room temperature is about 4℃, freezing room temperature is about-18℃). After manual adjustment, the average temperature in the refrigerator will generally be adjusted after 6 hours. The 2 2-hour principle: No food-even a turkey that is not easy to cook-should be prepared for more than 2 hours before cooking. Once food is completely exposed to room temperature for a long time, bacteria will grow rapidly, so the chances of consumers getting sick will increase. So, what food needs to be refrigerated? The answer is: any wet food is perishable, so it needs to be refrigerated. Don't think that mashed potatoes are necessarily much safer than roast suckling pigs. If you use improper preservation methods, it will still become a paradise for bacteria, which will make you hard to prevent. 3. It is best to arrange the food with a large amount of food to be cooked at the end to avoid more pollution in the process of taking out, making, serving and placing; Prepare small portions of food according to the standard of each guest 1 serving, take them out separately, and put the rest in the refrigerator or oven, and replenish them continuously during the banquet; Cold dishes can present the best flavor when the temperature is below 4℃, while hot dishes need to be kept at about 60℃, which is delicious without losing too much nutrition. 4 Be careful to pack large quantities of food. After cooking, the inedible parts of 1 rice should be separated in advance, cooled quickly and evenly, and then refrigerated; It is best to slice the meat food, wrap it with plastic wrap, and then put it in the refrigerator with other foods, so that it can not only cool quickly, but also make effective use of the refrigerator space; The last thing to do before closing the refrigerator is to label each food, indicating the name and cooking time. The refrigerator can't be too full, and the food in the refrigerator can't be too full, because refrigeration not only needs the right temperature, but also needs air circulation. Instead of filling the refrigerator with food to minimize the freshness of food and make it lose its original good taste, it is better to transfer the excess food directly to relatives, friends and neighbors, which not only enhances feelings, but also helps you eat delicately and healthily. 6 Reheat before eating In order to kill the bacteria in the frozen food, the food should be heated above 75℃ before eating the next day (the broth must be boiled for 3 minutes). If you don't know how to control the temperature, you can borrow a special thermometer in the kitchen to ensure the proper temperature is reached. Doing the above will be troublesome at first, but it is definitely worth doing. After forming good habits, it will no longer be a trivial burden. For the health of you and your family, you might as well practice seriously according to what is said in the article. 1. Buy fresh food to go home and refrigerate it as soon as possible. Buy fish, meat and seafood. , clean, dry and put in a clean fresh-keeping box. If you want to deal with it the same day or the next day, you can put it in the refrigerator. If cooking time exceeds 2 days, it should be stored in the freezer. 2. Pay attention to the shelf life of food. Most packages of frozen or refrigerated meat or fish are printed with shelf life, so you should pay attention to eating them before this date; If you bought it from a farmer's market and there is no shelf life, it is recommended to eat it within 7 ~ 10 days, and it is best to discard it after the shelf life. 3. Store raw and cooked food separately. Things in the refrigerator are stored in different areas, and cooked food and leftovers are concentrated on the upper layer of the refrigerator; Fresh fish, etc. It should be placed on the lower floor to avoid raw food polluting cooked food. 4. Clean the refrigerator every 1 ~ 2 weeks. Regularly clean and discard expired, stale and smelly foods, and wipe and disinfect the refrigerator with diluted bleach. 5. Pay attention to the refrigerator temperature. The temperature of the refrigerating room should be kept below 7 degrees Celsius, and the temperature of the freezing room should be below minus 18 degrees Celsius. Environmental taboo: 1. Plug in the power supply and detonate the refrigerator. If there are too many things in the refrigerator, it will affect the circulation of cold air and make the refrigeration and preservation effect worse. It's best to leave about 40% space in the freezer, and don't fill it up, and the freezer only stores food to be eaten in the near 1 ~ 2 weeks. In addition, don't block the food in the air outlet, so as not to affect the temperature in the refrigerator. 2. Switch the refrigerator frequently and open it for a long time. Every time you open the refrigerator, the temperature in the refrigerator will rise rapidly (about 5℃ ~ 20℃), and then it will take several minutes to restore the original coolness, which not only consumes electricity, but also is not conducive to food preservation. Earth refrigerator: put food in a box, put it in a vat, sprinkle sand around it, and water the sand from time to time. How to preserve food is a headache in outdoor activities. Some foods, such as biscuits, instant noodles and other packaged foods, are easy to preserve, while fresh meat, poultry, fish and shrimp, and fresh vegetables are easy to deteriorate and become inedible in hot summer. Generally, refrigerators, freezers and other equipment can not be carried in outdoor activities, so we can only take some local practical methods to process and preserve food according to local conditions. 1. Smoked food can prolong the storage time of food and tastes delicious, such as bacon, chicken and fish. Sun drying or air drying can also preserve food for a long time. If you catch a fish in the wild, you can sun it as dried fish for preservation or eating. The method is as follows: cut the spine and head of the fish (don't cut off the belly of the fish) into one piece, remove the viscera and wash it, smear salt on both sides of the fish, spread it on the fish head with bamboo chips or wooden sticks, hang it up or spread it flat in the sun, and dry it into dried fish in a few days for long-term consumption. Air-dried meat and poultry is also a food preservation method. Air-dried mutton and air-dried beef, a kind of food that Tibetans like to eat, belong to this kind of food. Every autumn, beef is hung in the shade, blown by dry wind, and dried to remove water from the meat. Generally, this air drying method is not suitable for areas with high water content in the air in the mainland, and can only be used in areas with dry air and low humidity in the Qinghai-Tibet Plateau and northwest China. As the name implies, air-dried food is dried with hot air and must not be dried in the sun. Another way to make food by wind is to rub it with salt and other condiments, or soak it in soy sauce and hang it in the air until the meat hardens. For example, wind-dried food such as wind eel, wind chicken, wind herring, wind *, beef, etc., the meat quality should not be too thick (too thick to air dry) or too salty. When eating, the food blown by the wind is made for cooked food. Perishable foods can also be sealed in plastic bags and stored in flowing river water during outdoor activities. We seal the mutton in a three-layer plastic bag, put it in a glacier, press it with stones, and take it as you eat, which can keep the meat quality unchanged for 20 days. Don't put the meat directly in the water without packaging, the soaked meat will lose its nutrition and the sediment in the river can't be eaten. 1 year ago