With the development of science and technology and the improvement of people's living standards, the types of modern food have become more and more diversified. In order to cater to the public's taste and achieve convenience and food safety, most of them use vacuum packaging. However, during the packaging process, there are always Microorganisms such as bacteria enter the packaging bag, causing the food to deteriorate. In order to improve this situation, many sterilization methods are used today. The autoclave is not only a sterilization instrument often used in medical treatment, but can also be widely used in food processing to sterilize food. This article mainly discusses the role of autoclave in food processing.
Autoclave overview
High-pressure steam sterilization is widely used and efficient, and is the most commonly used sterilization method in microbiology experiments. This sterilization method is designed based on the principle that the boiling point of water increases with the increase of steam pressure. When the steam pressure reaches 1.05kg/cm2, the temperature of the water vapor rises to 121°C. After 15 to 30 minutes, all kinds of microorganisms and their spores or spores on the items in the pot can be killed. General culture media, glassware, infectious specimens and work clothes can all be sterilized by this method. High-temperature sterilization mainly includes high-pressure steam sterilization, dry heat sterilization and burning sterilization. Steam sterilization belongs to moist heat sterilization. Due to the potential of moist heat sterilization, the temperature of the object to be sterilized is lower than that of steam. , steam condenses into water on its surface and releases potential, which can quickly increase the temperature of the object to be sterilized.
And because water and water vapor have larger heat capacity, faster heat conduction, and stronger penetrating power than air, sterilization requires a lower temperature and a shorter time than dry heat sterilization. Since the temperature of water vapor in high-pressure steam sterilization increases with the increase in pressure, the high-temperature steam used for sterilization is obtained by pressurization. Food packaging sterilization solves the problem of secondary food contamination caused during the food packaging process or the processing and sterilization of food after packaging. To date, heat sterilization is still the most important and effective method for food sterilization. Since low-temperature sterilization cannot kill all microorganisms, especially spores, low-temperature preservation is required, but the shelf life is only 3 months at most. In order to extend the shelf life, cans (including tin packaging and flexible packaging) must be sterilized by high temperature and high pressure (i.e. 121°C). In this way, they can be stored for more than 2 years. However, in order to ensure the fragrance, current manufacturers generally only specify a shelf life of half a year or one year. For High-temperature sterilization requires packaging materials with high isolation and certain cooking resistance, such as tinplate, aluminum foil bags, PVDC film, etc.
The role of high pressure sterilizer in food processing
1. Use and precautions of autoclave machines
Add an appropriate amount of water to the outer autoclave, put the items to be sterilized into the inner autoclave chamber, cover the pot and twist the spiral symmetrically. Heating causes steam to be generated in the pot. When the pressure gauge pointer reaches 33.78kPa, open the exhaust valve to discharge the cold air. At this time, the pressure gauge pointer drops. When the pointer drops to zero, close the exhaust valve and continue heating. The steam in the pot increases and the pointer of the pressure gauge rises again. When the pressure in the pot increases to the required pressure, reduce the firepower. According to the characteristics of the items to be sterilized, maintain the steam pressure at the required pressure for a certain period of time, and then turn the sterilizer Turn off the power or fire, let it cool naturally, and then slowly open the exhaust valve to remove the remaining air before opening the lid to take out the contents. Items to be sterilized should not be placed too tightly. The cold air must be fully eliminated, otherwise the temperature in the pot will not reach the specified temperature and the sterilization effect will be affected.
After sterilization is completed, do not deflate or reduce pressure, otherwise the liquid in the bottle will boil violently, flush out the cork and overflow or even cause the container to burst. The lid cannot be opened until the pressure inside the sterilizer drops to equal to the atmospheric pressure. Also known as: autoclave, high-pressure sterilizer, high-pressure steam sterilizer, hand-raised pressure sterilizer, hand-raised pressure sterilizer, portable autoclave, portable high-pressure sterilizer, portable high-pressure steam sterilizer The cotton plugs of test tubes or bottles containing culture media in sterilizers, portable high-pressure steam sterilizers, etc. should be wrapped with oil paper or kraft paper to prevent condensation water from entering. In order to ensure the sterilization effect, the sterilization effect should be checked regularly. The common method is to place sulfur powder (melting point: 115°C) or benzoic acid (melting point: 120°C) in a test tube, and then conduct a sterilization test. If the above substances melt, it means that the temperature in the high-pressure steam sterilizer has reached the requirements and the sterilization effect is reliable. You can also affix the tape (with a temperature-sensitive indicator on it) for testing the sterilizer effect to the outer packaging of the items to be sterilized. If the indicator on the tape changes color, it also indicates that the sterilization effect is reliable. Nowadays, there are microcomputer-controlled high-pressure steam sterilizers. Just turn off the air conditioning, and the instrument can automatically set the constant pressure and time. When the time is up, it will automatically cut off the power and sound the whistle. It is very convenient to use.
2. Function
It is suitable for medical and health undertakings, scientific research, agriculture and other units to sterilize medical equipment, dressings, glassware, solution culture media, etc. It is an ideal equipment. The portable autoclave is a necessary inspection equipment for food factories and drinking water plants to obtain QS and HACCP certification. It can prevent food from being contaminated and make it clearer to eat.
3. Application of autoclave in food processing
It is generally believed that the three-dimensional structure (quaternary structure) of proteins collapses under high pressure and denatures, thereby inactivating bacteria. However, some people believe that all biological macromolecular substances composed of weak combinations, such as nucleic acids, polysaccharides, and fats, Substances or cell membranes will be affected by ultra-high pressure, especially through shear force, which will rupture the biological membrane, thereby affecting or even stopping the life activities of the organism, which can achieve sterilization, insecticide and effects. High-pressure sterilization avoids various disadvantages that affect food quality caused by heat treatment, and maintains the original flavor, color and nutritional value of food. Because it is an instant compression process of liquid medium, the sterilization is uniform, pollution-free, safe to operate, and consumes less energy than the heating method, reducing environmental pollution. Put the equipment and reagents to be sterilized into the high-pressure steamer.
The liquid in the bottle should not exceed 213. Tighten the lid and loosen it a circle, or wrap it tightly with aluminum foil. When starting high-pressure sterilization, open the exhaust port first. , wait for the hot water steam to discharge for a few minutes, close the valve and sterilize at 121 degrees for 20 minutes. Release the gas after the pressure drops to 0: After sterilization, let the bottle cool and tighten the bottle cap in time; you can leave a gap in the high-pressure steamer lid and heat it to 100 degrees. After cooling, the equipment in the high-pressure steamer will also automatically Dried. Generally, the equipment can be turned on for 15-20 minutes, and the liquid can be turned on for 30 minutes. High-temperature and high-pressure steam sterilization relies on steam sterilization. If the items to be sterilized are placed too closely and steam cannot penetrate, the sterilization effect cannot be guaranteed.
Therefore, it is necessary to leave gaps in the placement of the sterilized items, and the package will not be too large. Tightly, the sterilizer should be operated by trained and qualified personnel, and the entire sterilization process should be supervised by a dedicated person. cannot completely rely on automatic water level protection, you should always pay attention to the water level to avoid burning out the electric heating tube. . When adding water manually. You should first cut off the power supply, open the vent valve 3 to relieve pressure, and then open the water inlet valve to add water. Never open the water inlet valve when there is pressure in the mezzanine, The vent valve should be open when adding water. When there is pressure in the sterilization chamber, the interlocking handle cannot be lifted, and the door cannot be forced to open. Steam should be released slowly after sterilizing the liquid. The door can only be opened when the liquid temperature drops below 70°C. It is prohibited to open the door immediately after sterilization. If the sterilization temperature drops below the sterilization temperature due to a power outage or other reasons during the sterilization process, the timing should be restarted when the temperature reaches the sterilization temperature again. Pull the safety valve handle several times a week when there is pressure in the mezzanine to ensure that the safety valve is working properly. After each shift, remove the storage plate of the sterilizer, wipe it dry with a cloth and keep the sterilization chamber dry.
3. Conclusion
High-pressure sterilizers are operated by personnel who have obtained special equipment qualification certificates, are familiar with and master the performance of the high-pressure cookers, and use them in accordance with the instructions. Ability to perform routine care and maintenance. .Stick to the job, have safety awareness, and do not leave the job without authorization. If you need to leave, there must be a designated person to take care of you. At the same time, complete the shift handover registration. .Check whether the power supply and performance of the autoclave are in good condition before working. Is the water level within the normal range? Clean the surface of the autoclave every day, keep it clean and free of stains and oil stains, and record the time, pot times and item names of the sterilizer every day. There is a dedicated person responsible for the maintenance of the autoclave every week, and there are records. There is a dedicated person responsible for the maintenance of the autoclave every month, and there are records. The equipment department is responsible for monitoring the pressure gauge of the autoclave every year. Make sure the equipment is in good and safe working condition. The head nurse is responsible for liaising with general affairs. For problems that arise during the use of the autoclave, the head nurse or the designated person in charge can directly contact the central sterilization supply center. Operators are not allowed to operate in violation of regulations, otherwise they will be punished according to the circumstances. According to the role of high-pressure sterilizers in food processing, food safety is reduced and food poisoning is alleviated.
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