Common sterilization techniques in aseptic packagi

2022-08-19
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The common sterilization technology in food aseptic packaging

ultraviolet sterilization is a simple sterilization method, which has no reagent residue, high efficiency, fast speed, and can be reflected by different surfaces, with weak penetration. It has an ideal sterilization effect on liquid materials. When in use, liquid materials, such as beverages and milk, can be sterilized by passing through the ultraviolet irradiation area in a thin layer. Ultraviolet sterilization can be applied to the sterilization of food surfaces, food packaging materials, food processing workshop environment, equipment, appliances, and worktables. However, the ultraviolet ray must be irradiated to sterilize, and it cannot be sterilized unless it is irradiated. In addition, the intensity of ultraviolet ray is reduced in proportion to the square of distance when it propagates in a straight line. The sterilization effect is related to the irradiation intensity, time, distance and air temperature. Therefore, it is necessary to determine the irradiation distance and time according to the power of ultraviolet lamp. In addition, UV sterilization is also related to the surface state of materials. For packaging materials with smooth and dust-free surface, UV can kill bacteria on the surface; For the embossed aluminum foil surface, the sterilization time is three times longer than that of the smooth surface; For the irregular shape of the packaging container surface, the sterilization irradiation time is five times longer than the plane. At the same time, the characteristics of materials should also be considered when using ultraviolet sterilization, especially the inner layer of composite materials, such as PVC, PVDC, LDPE and other materials, will reduce their heat sealing strength by about 50% after ultraviolet irradiation. If ultraviolet ray is used in combination with air heating, hydrogen peroxide, ethanol and other sterilization methods, its sterilization ability can be greatly enhanced

magnetic sterilization technology

magnetic sterilization is to place the food that needs sterilization in the magnetic field, and under the action of the set magnetic field strength, so that the food can be sterilized at room temperature. Because this sterilization method does not need heating and has the function of broad-spectrum sterilization, the flavor and quality of the processed food will not be affected. This sterilization method is mainly applicable to all kinds of beverages, liquid foods, condiments and other packaged solid foods

high voltage electric field pulse sterilization technology

high voltage electric field pulse sterilization is to place food in the instantaneous high voltage electric field generated between two electrodes. Because high voltage electric pulse (Heep) can destroy the cell membrane of bacteria, change its permeability, and kill cells. There are two ways to obtain high-voltage pulsed electric field. One is to use the principle of LC oscillation circuit, first charge a group of capacitors with high-voltage power supply, connect the capacitors with an inductive coil and the electrodes of the processing room, and the high-frequency exponential pulse attenuation wave generated when the capacitors are discharged is added to the two electrodes to form a high-voltage pulse electric field. Due to the fast discharge electrode of LC circuit, the electric field energy can be released within tens to hundreds of microseconds. Using the automatic control device, the LC oscillator circuit can be continuously charged and discharged, and the sterilization process can be completed within tens of milliseconds. The other is to use a specific high-frequency high-voltage transformer to obtain a continuous high-voltage pulsed electric field. The intensity of high-voltage pulse electric field for sterilization is generally 15 kV/cm ~ 100 kV/cm, the pulse frequency is 1kHz ~ 100kHz, and the discharge frequency is 1kHz ~ 20kHz. High voltage electric field pulse sterilization is generally carried out at room temperature, and the treatment time is dozens of milliseconds. This method has two characteristics: first, due to the short sterilization time, the energy consumption in the treatment process is far less than that of heat treatment. Second, because it is carried out under normal temperature and pressure, the processed food has little change in physical properties, chemical properties and nutritional components compared with fresh food, and there is no perceptible difference in flavor and taste. Moreover, the sterilization effect is obvious, which can meet the requirements of commercial sterility, especially suitable for heat sensitive food, and has a broad application prospect

pulse strong light sterilization technology

pulse strong light sterilization technology adopts the method of strong white light flash for sterilization, which is composed of a power unit and an inert gas lamp unit. The power unit is a component that can provide high voltage and high current pulses. It provides energy for the inert gas lamp. The inert gas lamp can emit light from ultraviolet to near-infrared region. Its spectrum is very similar to the sunlight, but its intensity is thousands to tens of thousands of times stronger, and the light pulse width is less than 800 μ s。 Because this technology only deals with the surface of food, it has little impact on the flavor and nutritional components of food. It can be used to extend the shelf life of food packaged with transparent materials and fresh food. The research shows that pulsed strong light has a strong lethal effect on Bacillus subtilis and yeast. After more than 30 flashes, the number of these bacteria can be reduced from 105 to 0. The sterilization effect of pulsed strong light may be ultraviolet, but other bands may have synergistic effect

excited ultraviolet pulse sterilization technology

this is one of the most promising sterilization technologies developed recently. The excited UV pulse uses the zigzag yield strength to replace the zigzag strength sterilization technology, which is different from the conventional physical sterilization means. Using a special light source and power supply device, the UV with a single wavelength of 253.7nm is generated under high frequency and high pressure. Its intensity can reach more than 200MW/cm3, which is 200 ~ 300 times that of the conventional UV device. Its pulse can reach the nanosecond level, and its energy is enough to break the C-H bond in the cell DNA structure The C-N bond and O-H bond can cause fatal damage to the DNA structure. If they cooperate with low concentration hydrogen peroxide, they can not only increase the sterilization intensity, but also decompose the residual hydrogen peroxide. The application of this new technology will provide strong technical support for the microbial fence system of sterile packaging equipment

ultra high pressure sterilization technology

in recent years, Japan has developed a new type of food processing and preservation technology, which is ultra-high pressure sterilization technology. Ultra high pressure treatment has some advantages that heat treatment and other processing methods do not have. It can maintain the original flavor components, nutritional value and color of food (such as meat), and kill common yeast, Escherichia coli, Staphylococcus, etc. in food to achieve the purpose of sterilization. The so-called high static pressure technology (HHP) is to seal the food in an elastic container or place it in a sterile pressure system (water or other fluid medium is often used as the medium to transmit pressure), and treat it under high static pressure (generally above 100MPa) for a period of time, so as to achieve the purpose of processing and preservation. Under high pressure, proteins and enzymes will denature, and the nuclear membrane of microbial cells will be compressed into many small fragments and protoplasm into a paste. This irreversible change can cause microbial death. The death of microorganisms follows the first-order reaction kinetics. For most non spore microorganisms, the sterilization effect is good at room temperature and 450MPa pressure. Spores of spores are pressure resistant, and sterilization requires higher pressure, which is often combined with heating and other treatments to be more effective. Temperature and medium have a great influence on the mode and effect of ultra-high pressure sterilization of food, such as room cleaning. Intermittent repeated high-pressure treatment is a good method to kill pressure resistant spores. The ultra-high pressure sterilizer newly developed in Japan has an operating pressure of 304mpa ~ 507mpa. The greatest advantage of ultra-high pressure sterilization is that it has no impact on the flavor substances, vitamin C, color rope, etc. in food, and the loss of nutrients is very small. It is especially suitable for the sterilization of fruit juice, jam, meat and other foods. In addition, when using 300mpa ~ 400MPa ultra-high pressure to sterilize meat, it can also save energy and have a good effect, breaking muscle fibers and improving the tenderness of meat food

high hydrostatic pressure sterilization technology

high hydrostatic pressure technology uses liquid as the pressure medium to make food under high pressure and achieve the purpose of sterilization. Its operating temperature is low and its heat damage to food is small. The processed products are suitable for aseptic filling. A professor from the University of Georgia in the United States used continuous high hydrostatic pressure equipment to sterilize the orange juice, and then filled it with laboratory sterile packaging equipment. The product was stored at 40 ℃ without any deterioration for 90 days, and maintained its original color and flavor. Its aseptic packaging equipment is composed of box, nitrogen delivery pipe, high temperature and high pressure steam delivery pipe and material delivery pipe. For filling, put the packaging container into the box, put high-temperature steam for sterilization, then put the materials after high-pressure sterilization, and finally fill nitrogen for sealing until the oil level reaches 1.5 of the sight glass

ultrasonic sterilization technology

ultrasonic is a sound wave with a frequency greater than 10kHz. Like ordinary sound waves, ultrasonic waves belong to longitudinal waves. The interaction between ultrasonic wave and sound transmission medium contains huge energy. When encountering materials, it will produce rapid alternating compression and expansion. This energy is enough to kill and destroy microorganisms in a very short time, and it can also produce a variety of effects on food, such as homogenization, aging, cracking macromolecular substances, etc., with multiple effects that are difficult to be achieved by other physical sterilization methods, So as to better improve food quality and ensure food safety. Technicians used ultrasonic generator as sterilization equipment and soy sauce as sterilization object, and achieved good results

membrane filtration sterilization technology

with the development of material science, various membranes that can be used for material separation appear one after another. Membrane separation technology has been widely used in industrial production such as food and Biopharmaceutics, such as the extraction of biochemical substances, the preparation of pure water, the concentration of fruit juice, etc. the membrane separation process can be divided into two types according to the different driving forces. One is membrane process driven by pressure, such as ultrafiltration; The other is the membrane process driven by electricity, which is called ion exchange, such as electrodialysis. Membrane processes driven by pressure can be divided into microporous filtration, ultrafiltration and reverse osmosis according to the pore size and retention capacity of the membrane. Generally, the pore diameter of the membrane is 0.0001 μ m ~ 10 μ m, while the size of microbial particles in the material is generally 0.5 μ m ~ 2 μ M. If a membrane with a pore size smaller than that of microorganisms is selected, and the feed liquid is filtered through the membrane filter, the bacterial particles are intercepted, which is called filtration sterilization. Membrane filtration sterilization technology has the advantages of low energy consumption, operation at room temperature, suitable for heat sensitive materials, strong process adaptability and so on. Its application prospect is broad. It has been widely used in the filtration and sterilization of food, biochemistry, pharmacy, water, air, dairy products, fruit juice and so on

ozone sterilization technology

the mechanism of ozone sterilization is that O3/H2O forms a strong oxidation electrode potential, so it can destroy the phospholipids and proteins in the cell membrane and cell wall of microorganisms. When O3 enters cells, it will destroy enzymes and genetic material, thereby killing microorganisms. Ozone and water are mixed to form ozone water, which can replace hydrogen peroxide to treat sterile packaging containers. At the same time, due to its half-life (5 ~ 14 minutes), ozone is extremely unstable in water, and the reduction reaction always occurs, producing monatomic oxygen with strong oxidation. At the moment of its production, it has a chemical reaction with lipoproteins in the bacterial cell wall or phospholipids and proteins in the cell membrane, so that the bacterial cell wall and cell membrane are destroyed, the permeability of the cell membrane is increased, and the substances in the cell flow out, making the bacteria inactive. At the same time, ozone can quickly spread into the cell, oxidize the enzyme or HNA, DNA in the cell, and then cause the death of Mycoplasma. Ozone sterilization has the advantages of high efficiency, rapidity, safety and low cost. Since its discovery in 1785, it has been widely used in food processing, transportation and storage, and the production of tap water and purified water. The sterilization speed of ozone water is 300 ~ 1000 times faster than that of chlorine water. At the same time, ozone is also very effective in environmental sterilization and can also remove odor

hydrogen peroxide (double

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