Food preservation methods, food sometimes needs to be preserved, each food has its own preservation methods, some methods can extend the shelf life and shelf life of food, and some methods can also increase the flavor of food. Let's take a look at the food preservation methods and related information.

Food preservation method 1 1, ultra-low temperature preservation.

Preserving food at ultra-low temperature can inhibit the growth of microorganisms and reduce the decay rate of food, but it is still unknown whether it can completely kill microbial strains. Pay attention to the control of temperature when storing at ultra-low temperature. Generally speaking, the lower the temperature, the longer the storage time will be.

2, high temperature sterilization

Under the condition of high temperature solution, the components can kill most germs and enzymes. If sealing, vacuum pump and rapid refrigeration are used to solve the problem, it can reasonably slow down the decay and mildew of ingredients and increase the storage time. For example, we often drink bagged pure milk, wine, pasteurized milk and so on.

3. Dehydration and drying

Dehydration is to reduce the moisture in food to a certain extent, so that microbial strains are not easy to grow, develop and reproduce, and the activity of enzymes will be inhibited. The common dehydration methods at home are wind and sun, air drying, heating volatilization or freeze drying. It is worth reminding that the way of exposure is very simple, but it is also the most destructive to vitamins.

4, improve plasma osmotic pressure

This name seems incomprehensible, but in fact most people have used this method. For example, pickling ingredients with salt or sugar. When the concentration of salt is 8%- 10%, it can inhibit the reproduction of most microbial strains, but it cannot be completely eliminated. In order to eliminate microbial strains, the concentration of salt should be controlled at15%-20%; The sugar concentration of candied food should be controlled at 60%-65% to inhibit the propagation of microbial strains. In the case of storage, pay attention to sealing and moistureproof. Common candied foods include dried fruits, preserved fruits and applesauce.

5. Increase the concentration of hydroxyl ions.

Most bacteria can't grow and reproduce normally in the natural environment with pH lower than 4 or 5, so they can be preserved by increasing the concentration of hydroxyl ions. Vinegar pickling is adding edible vinegar to food, which is common in vegetables and fruits, such as pickles, pickles and sour radishes.

Food preservation method 2 1, cold storage method: 20~25 degrees Celsius is the most suitable temperature for mold growth, and 35 degrees Celsius is the most suitable temperature for bacteria growth, so lowering the temperature can inhibit the growth of bacteria and prolong the storage time of food. Generally, fruits and vegetables should not be frozen, only refrigerated, and it is best to eat them within two days. If you don't eat meat for more than two days, you should freeze it.

2. Air-drying method: The moisture in food is necessary for the growth of microorganisms. If food can be dehydrated, the growth of microorganisms can be inhibited. Usually, the shelf life of air-dried fish, air-dried meat and dried vegetables we eat is longer than that of fresh ones.

3. Pickling method: Salt has bactericidal effect, and its high permeability can dehydrate bacteria, so food pickled with salt can be preserved for a long time. Such as bacon, salted fish and pickles.

4, sugar pickling method: sugar pickling method to preserve food, and the principle of salt pickling method to preserve food is roughly the same, the same is that high permeability can dehydrate bacteria, in order to achieve the role of inhibiting bacterial growth. For example, candied fruit shops and sweet-scented osmanthus candy can be preserved for a long time without deterioration.

5. Smoke method: Incomplete combustion of wood contains hundreds of compounds, such as formaldehyde, acetic acid and wood oil. Covering the surface of food can prevent the formation of spores and the breeding of mold and bacteria. Heating dry food while smoking can also inhibit the growth of bacteria. Such as bacon, duck and fish. But these foods usually contain carcinogens and should not be eaten more.

6, vacuum packaging: vacuum packaging of food because there is no oxygen, and in a sealed state, bacteria and fungi can not enter, aerobic breathing bacteria can not survive, so the shelf life will be longer.

Food preservation method 3 1, drying and dehydration

This preservation method is to prevent mildew by removing water from food. The purpose of fermenting bacteria and bacterial growth. For example, using the sun to dry fruits can achieve the purpose of preservation. Now, all kinds of equipment can moderately dry food by controlling the temperature of the air.

2. Quick freezing and drying

This is a dehydration process, and food does not need to be preserved or refrigerated. When food absorbs water, it will return to its original state and taste. This method can be used to preserve various foods. Freeze food in the refrigerator, take out the air in the refrigerator and the ice will evaporate. This process is called quick freezing and drying.

3. Cooling and freezing

Refrigeration is a way to preserve food, but this method will not kill microorganisms, but will only inhibit their reproduction. The lower the refrigeration temperature, the longer the food will be preserved. The temperature of the cold storage room is generally controlled between 1-7 degrees, which can prevent food from rotting in a short time. Food must be preserved by deep freezing before use. Most frozen foods can be stored at-17 degrees for one year and at -28 degrees for two years.

4. Quick freezing

Quick freezing is to put food in a shallow box, put it on a hollow shelf, and freeze it for 60-90 minutes according to the size of the food through low-temperature refrigeration and extrusion, so as to achieve the purpose of freezing the food. Spray freezing device, also known as cryogenic freezing, is a method of freezing food at extremely low temperature by using liquid nitrogen or carbon dioxide, which is faster than any other method.

5. Cold cooked food

Cook the food according to the standard cooking method, then put it into an airflow cooler, reduce the temperature of the food to 3 degrees, and store it in the refrigerator at this temperature. When the cooked food is taken out of the cold storage, the temperature can meet the use requirements only by using a specially designed dish loading furnace for 12-20 minutes of heat exchange (without cooking).

1, cold storage and freezing method

Refrigeration and freezing method is the most commonly used way in family life at present, and the refrigerator is mainly used for refrigeration and freezing. The refrigerator has a special freezing area and a cold storage area. The temperature in the frozen area shall be controlled at minus 18~ minus 20 degrees. It can store food for a long time, for a month, months or even a year or two without any problems. Refrigeration is a good way to preserve food in a short time. The temperature is about 4 degrees, which can inhibit bacteria. If you can't finish eating food, you need to put it in the refrigerator for 2~3 days.

2, vacuum preservation method

Vacuum preservation is the most popular and applicable method at present. The main principle of vacuum preservation method is to isolate food from air, which will inhibit the growth of bacteria, so prepare a vacuum bag, put food in it to extract air, and seal the bag mouth.

3. Air drying method

Air drying method is mainly based on the dehydration principle of food, so that there is no breeding environment for bacteria, so that food can be well preserved. Air-dried beef, air-dried fish, air-dried dried vegetables, etc. This is how everyone usually eats and drinks.

4. Pickling method

There are two kinds of pickling methods, one is to pickle with sugar and the other is to pickle with salt. As we all know, salt actually has the function of sterilization, so putting salt on the surface of food can play the role of antisepsis and sterilization. High concentration of sugar can actually inhibit the growth of bacteria, so it is also very desirable to preserve food with sugar and salt.

Let me share with you the methods of food preservation. In addition to the methods mentioned above, there are some foods you usually encounter that you don't know how to preserve. It is most effective to put them in the refrigerator for cold storage or freezing. Therefore, everyone should choose the most suitable preservation method to preserve food according to its different properties.