The recurrence of the epidemic has made some people stay at home longer than expected. Since March, more than 320,000 cases of local infection have affected 30 provinces, of which Shanghai and Jilin are the first to bear the brunt.
Three meals a day are cooked at home, and the consumption of various ingredients has increased significantly. The difficulty of purchasing materials during the sealing period increased, and many netizens said: "Finally realized the necessity of proper hoarding."
Frozen food has become one of the must-stocks during the epidemic period because of its shelf life and long shelf life.
"Life Times" (search for "LT0385" in WeChat to follow) interviews experts and gives you the best "storage schedule" for frozen food, so that you can ensure nutrition and safety on the basis of ensuring basic survival.
Experts interviewed
Postdoctoral Fellow in Nutrition and Food Safety, China Agricultural University
Tang Molian, a dietitian in the Department of Clinical Nutrition, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine
Frozen food is preferred for home stockpiling
Under the epidemic situation, frozen food has become the preferred choice for households to stock up on grains and oils in addition to rice and flour.
Under frozen conditions, microorganisms cannot multiply, so there is no need to add preservatives, and frozen foods can be stored for a long time. Common frozen foods mainly include fruits and vegetables, meat and poultry, and aquatic products.
Frozen vegetables: land-saving and convenient
The freezing area in the supermarket has a variety of frozen vegetables, such as peas, broccoli, corn kernels, carrot slices, etc., it is recommended that you save some in moderation, and you can be emergency when there is no fresh vegetable.
After the frozen vegetables are taken out of the refrigerator, they can be cooked directly with boiling water, which is very convenient.
When buying frozen vegetables, it is best to choose products with complete seals, shiny surfaces, and no large amount of frost crystal residue.
Some people think that frozen vegetables are very low in nutrients, in fact, although frozen vegetables will lose a little water-soluble vitamin C and B vitamins, but dietary fiber, minerals, carotenoids, vitamin E, etc. have been well preserved.
You can also make some frozen vegetables at home:
Choose some vegetables that are suitable for freezing, such as peas, broccoli, carrots, etc.
Blanching the vegetables into a shape suitable for cooking can kill bacteria on the one hand, and make the color of the vegetables better on the other hand.
After blanching, drain and pack in small packages to avoid safety hazards caused by repeated thawing.
Don't freeze for too long, try to eat it within two months.
Meat and poultry: small nutrient loss
Under extremely low temperature conditions, the moisture in the meat will be frozen into ice crystals, resulting in frozen degeneration of proteins and a series of changes in physical and chemical properties, which will indeed affect the taste and may be relatively dry and hard to eat.
However, the content of protein and minerals will not change during the preservation process, although a small part of soluble proteins, salts, vitamins and other water-soluble nutrients will be lost, but it will not affect the core nutrients.
To go to regular supermarkets and stores, choose to buy products produced by qualified enterprises; pay attention to the production date, shelf life and QS logo of the product; the product packaging should be sealed completely; the surface of the product is shiny, without a large number of frost crystal residues; touch the surface of the product, the feel is hard, and there is no softening phenomenon; meat and poultry products do not have a large amount of blood, water, ice residue.
Fresh aquatic products: dehydrated and then frozen
Fresh fish, shrimp, shellfish and other high moisture content, after the home refrigerator is frozen, its taste will change significantly, such as meat loss of elasticity, loose muscles and so on. Therefore, it is not recommended to stock up on fresh aquatic products in large quantities.
If you have already purchased fresh aquatic products, you can do some simple treatment before storing them. For example, blanch shrimp, shellfish blanch, marinate fish with ginger shreds, salt, cooking wine, chili peppers, etc., and then divide the ingredients into small portions and freeze them.
After treatment, it helps the ingredients to dehydrate to a certain extent, which can reduce the damage of freezing to the taste of meat.
Frozen food has a "storage schedule"
Refrigerators can keep food fresh and extend their eating time, but refrigerators are not equal to safes, and different foods are refrigerated (about 4 ° C) or frozen (about minus 18 ° C) have specific safety time limits.
The storage time of frozen meat is related to both the storage temperature and the variety of meat and the freshness of the meat before freezing.
Pre-treatment has a great impact on the shelf life of frozen foods, and a few hoarding tips for extending shelf life are shared:
1. Fresh fish is frozen without any treatment, and can only be stored for 1 to 2 months; but after scientific treatment and then frozen, the shelf life can be extended to half a year.
2. Poultry, seafood, and river fresh should be cleaned and cleaned, washed and then frozen inside and out; other foods and meats should also be carefully cleaned before freezing to remove bacteria on the surface.
3. All food should be divided into one-time portions before being placed in the freezer room, carefully packaged in a plastic bag or plastic wrap to prevent moisture loss.
4. It is best to put a label with date and name on the outer packaging for easy access later.
Thawing foods is not recommended for blistering
Some people like to soak frozen food in hot water, so that although the thawing speed is fast, the ice crystals in the food will break through the cell wall when thawing, so that the fat in the food will run out in advance, affecting the nutrition and taste of the food.
There are also people who like to soak food in tap water to thaw, which is also easy to cause nutrient loss, damage the taste of food, and lead to the growth of microorganisms.
In a word, the way to thaw with blisters, we don't recommend it!
The method of thawing food at room temperature is also not scientific. Most pathogenic bacteria multiply in large quantities in environments of 5 ° C to 60 ° C, and thawing at room temperature usually takes more than 2 hours, which gives bacteria a full chance to grow.
Two nutrient-preserving and safe methods of thawing are recommended:
01
Thaw in advance in a cold room
Remove the food to be thawed from the freezer in advance, pack it in a crisper box or plastic bag, and put it in the lower layer of the refrigerator's refrigerator, where it can be used for cooking after thawing.
This method is most recommended, safe and convenient. The only disadvantage is that it takes a long time, and generally large pieces of meat should be placed in the refrigerator at least 12 hours in advance, and the time of small pieces can be halved.
Therefore, it is recommended not to put the whole piece of meat directly into the refrigerator, but to cut it into small pieces before freezing the food, or directly cut into shredded meat or slices of meat, according to the amount of consumption at a time, wrapped in a plastic bag or plastic wrap into a thin layer, and frozen in separate packages.
02
Thaw in a microwave
If you are in a hurry to cook, you can use the microwave oven to complete the thawing in a few minutes, and the microwave thawing is heated from the inside of the food, the thawing time is short, and the nutrient loss is small. However, the temperature setting should not be too high when the microwave is thawed, otherwise it will cause protein denaturation and water loss.
Moreover, the shape of the ingredients to be thawed should be as regular as possible, preferably flattened, and the heating is more uniform; if you do not know how long is the most appropriate, you must try a relatively short time first. ▲
Editor of this issue: Liu Yunxuan
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