1, flame sterilization
Flame sterilization is a method of sterilization by flame burning at high temperature.
Heat-resistant inoculation ring, inoculation spatula, inoculation spoon, inoculation needles, etc., through the flame burning, can be completely sterilized, the mouth of the test tube and the mouth of the glass vials, through the flame a few times, the temperature can reach more than 200 ℃, all the microorganisms and buds, can be completely killed to achieve the degree of sterility. Flame sterilization in the canning industry is the use of flame to directly heat the cans, is a high temperature at atmospheric pressure for a short period of time sterilization.
Sterilization of cans after preheating in the high-temperature flame (temperature of 1300 ℃ or more) rolled over, a short period of time to reach high temperatures, maintained for a short period of time, after the water spray cooling. Food in the can may not need soup as a convective heat transfer medium, the contents of the solids content is high. Because of the high pressure in the can when sterilized, generally only used for small metal cans. The sterilization temperature of this method is more difficult to control (generally determined by measuring the heat radiated from the can after adding).
2, horizontal sterilization pot
Horizontal sterilization pot is the use of compressed air as the pressure of the cylinder sterilization equipment, the lid locking type is the use of self-locking wedge engagement method, open and close the start is convenient, adapted to canned goods, beverages, tinplate cans and glass cans sterilized processing work.
The pot body includes pot body, pot cover, safety interlocking device, turn ring, track, sealing ring, roller, locking wedge, steam, nozzle, cooling water pipe and gate valve.
General canned food factory for cans for atmospheric pressure boiling heating sterilization treatment are used in this form of horizontal sterilization pot, this equipment through the introduction of compressed air can be realized by counter-pressure sterilization. If the cooling needs to be carried out in the pot, a water pump should be used to pump into the spray pipe on the top of the pot (or a water circulation system). When sterilizing, the pressure inside the can will exceed the pressure outside the can (inside the pot) due to the heating that increases the temperature of the can.
Therefore, in order to avoid the sterilization of glass jars cans pressurized and jumped lid, tinplate cans protruding from the two end surfaces, it is necessary to apply counter-pressure, especially on the need for higher sterilization temperature of canned meats more on this. The use of counter-pressure sterilization, that is, with compressed air into the pot to increase the pressure to prevent the cans convex cans and jump cover, the operation is described as follows: due to the compressed air is not good thermal conductivity, the situation of steam itself has a certain pressure.
Therefore, in the sterilization process, do not put into the compressed air, and only after reaching the sterilization temperature in the insulation, only open compressed air into the pot, so that the pot to increase the pressure of 0.5 ~ 0.8 atmospheric pressure. Special after sterilization, cooling cooling, stop supplying steam, cooling water pressure into the spray pipe. Due to the temperature drop in the pot, steam condensation, and the pot force to reduce the use of compressed air pressure to compensate.
In the sterilization process, attention should be paid to the initial exhaust, and then release steam, so that the steam circulation. Can also be every 15-20 minutes deflation, to promote heat exchange. In short, must meet the provisions of the sterilization conditions, according to a certain procedure, the sterilization temperature, the size of the sterilization pressure, the length of the sterilization time and operation methods are specified by the canned product sterilization process.
3, pasteurization
The use of heat to kill pathogenic bacteria in the liquid or general bacteria, without seriously impairing the quality of consumption methods. Created by Pasteur to sterilize alcohol, hence the name. Heating 61.1 ~ 62.8 ℃ half an hour, or 71.7 ℃ 15 ~ 30 seconds. Commonly used to sterilize milk and alcohol, etc.
4, ultra-high-temperature sterilization
The heating temperature of 135 ℃ to 150 ℃, the heating time of 2 to 8 seconds, the heating of the product to achieve commercial sterility of the sterilization process. Ultra-high temperature sterilization can effectively kill microorganisms in a very short period of time, and better maintain the quality of food should be.
Simply put, under ultra-high-temperature conditions, the actual microorganisms are already killed before the nutrients are destroyed, so the nutritional value is effectively maintained and the purpose of sterilization is achieved. There is a big difference between pasteurization (Pasteur) and UHT (Ultra High Temperature Sterilization).
Precautions
If you use glass bottles for canning, you must ensure that the glass bottles are protected from sudden temperature rises and falls, resulting in rupture, and that the bottles are cleaned and sterilized before packaging.
So the requirement to add warm water before heating, the temperature of the water and the temperature of the can is equivalent or slightly higher, but not higher than 20 ℃, most of the time in the filling is hot filling, so that the bottles also have a certain temperature, in the cooling needs to be added to the cooling of hot water is lower than the temperature of the water in the pressure cooker.