Preservation is to ensure the taste and nutrition of food. Due to the different physiological characteristics of meat, fruits and vegetables, and aquatic products, scientific preservation methods are required. It is worth noting that for a particular product, no matter what advanced preservation technology is adopted, its shelf life is limited, and it needs to be processed as soon as possible before that. Next, I will introduce to you how to preserve the freshness of common foods in our daily life.
Aquatic product preservation
Salt preservation mainly includes dry pickling, wet pickling and mixed pickling. The dry salting method is to use the solid salt and the water precipitated from the fish to form a salt solution, and the fish is salted to preserve freshness; the wet salting method is to put the fish into a salt bin first, and then add a pre-prepared supersaturated salt solution for salting. The mixed pickling method is an organic combination of dry pickling and wet pickling.
Ice preservation is a method of preserving seafood by using natural ice or machine-made ice to reduce the temperature of fresh fish to near freezing point but not freezing. It is one of the most commonly used methods for fresh-keeping fish catches that are widely used by fishermen after salt preservation.
Other preservation methods Cold sea water preservation, micro-freezing preservation, preservative preservation, temporary preservation of live fish and other preservation methods.
Can dead aquatic products be eaten? Generally speaking, soft-shelled turtles, eels, river crabs, etc. are not edible if they die. In other cases, specific analysis.
The core temperature of pork, beef and mutton commodities must reach -18℃ before storage. The temperature of the cold storage is stable at -18 °C, and the suitable temperature in the cold storage room is -18 °C ~ -20 °C. In this case, the shelf life is generally 10 to 12 months.
The core temperature of poultry products must be below -18℃ before storage. The temperature of the cold storage should be kept at -18℃. The air temperature in the refrigerated room should be -18℃～-20℃. The shelf life of poultry is generally 8 to 10 months.
Thawing methods Low temperature thawing (from freezing to refrigeration), natural thawing, flow thawing, and microwave rapid thawing.
Precautions For frozen meat, repeated thawing and freezing should be avoided. When buying frozen meat, pay attention. If the product is yellow, white and dry, it may be stored for too long, so it is best not to buy it.
Vegetable preservation
Eggplant can be stored in a cool place for 3 to 4 days. There is a layer of wax on the surface of eggplants that can play a protective role, so don’t rush to wash the eggplants when you buy them home. You can put a layer of plastic wrap and store them in a cool place.
Carob beans are easy to dry after a long time. You can blanch them in boiling water for a while, then put them in a cool place to dry, then pack them in bags and put them in the freezer of the refrigerator. Keep fresh for one month.
Lotus Root Wash the lotus root, put it in a container, pour cold water, and the water should submerge the lotus root, and change the water every two days. The lotus root can be kept fresh for more than a month.
Do not wash the green peppers with water, dry them directly, put them in a fresh-keeping bag and store them in the refrigerator for about a week. Vegetables that should not be placed in the refrigerator: tomatoes, cucumbers, leafy vegetables, potatoes, onions, garlic, etc.
Fruit Preservation Food
Bananas It is recommended to hang the bananas in the vents, so as to avoid squeezing and blackening on one side. If there is no way to hang it, let the concave side face the table and the other side up, the same principle.
Watermelons should be stored in a cool place or in the refrigerator. You can also choose mature watermelons with a smooth surface and soak them in about 10% salt water for about 15 minutes, then put them in a plastic bag and seal them well, and store them in a cool place. place. This method can keep watermelon fresh for three months.
If you want to keep the oranges longer, you can slice the garlic, add water to boil, soak the oranges in the water for a few minutes after cooling, and then remove them for storage, which can be kept fresh for 3-5 months.
Lychees Wrap fresh lychees in newspaper, put them in plastic bags, and put them in the refrigerator. In this way, it can be stored for four or five days, the color of lychees is still fresh and tender, and the meat quality is still refreshing.
Frozen Food Preservation Food
Best Temperature In 1964, the International Society of Refrigeration recommended the maximum temperature for frozen food to be minus 18°C. The international community has unanimously recognized and firmly written this temperature into standards, norms and laws, and has continued to this day.
Shelf life at room temperature In summer, quick-frozen aquatic food can be kept at room temperature for up to one day, and quick-frozen agricultural food can be kept at room temperature for several hours; in winter, quick-frozen agricultural food can be kept at room temperature for one or two days, and quick-frozen aquatic food can be kept for two or three days. .
Selection Skills The surface of meat should be light red, and do not buy those that are black or red; Intact, undiscolored.
Precautions Do not put damaged or unpacked frozen food directly into the freezer; frozen food should be placed in the freezer, not the refrigerator; thawed food should not be refrozen; Do not overfill the freezer.
