Sterilization is one of the key technologies in aseptic packaging of food, which marks the success or failure of aseptic packaging. The scope of sterilization includes food, packaging materials (containers), working environment, equipment, and the like. Sterilization methods can be roughly divided into physical methods and chemical methods. The physical methods mainly include steam (high temperature), electromagnetic waves and irradiation. Steam sterilization is a classical sterilization method, and electromagnetic wave sterilization uses 2450 nm and 915 nm microwave sterilization and ultrasonic sterilization. Irradiation sterilization can be divided into ionic irradiation and non-ionic irradiation. Non-ionic irradiation uses a wide range of ultraviolet light with a wavelength of 253.7 nm. Due to the limitation of the intensity of the light source, there is no residual problem, but the above physical sterilization methods have certain limitations. Chemical methods mostly use strong oxidants, such as hydrogen peroxide, peracetic acid, ethylene oxide, halogen, etc. Chemical sterilization mainly relies on the oxidation ability of strong oxidants and the combination of -SH-thiol in cellular enzyme protein to convert to -SS - base, destroying the molecular structure of the protein, interfering with the metabolism of the bacterial enzyme system, rendering it inactive. According to molecular biology, it is the oxidative damage of the DNA of cells, thereby inhibiting the proliferation of cells. The use of chemical sterilization produces a certain amount of residual contamination of containers and packaging materials as well as equipment. Strict measures must be taken to control the residues to ensure the safety of the final product. To sum up, the sterilization techniques in aseptic packaging of foods are mainly as follows. Brand computer chips, dual-frequency integrated circuits, cross-magnetic induction detection, bringing higher accuracy, reliability and stability. 2. Automatic control system, using special magnetic materials and unique technology, the detection accuracy of the probe is particularly high, and the accurate position of the broken needle is displayed in 8 detection areas. 3. Dual probe design, double detection function, higher safety performance, compared with other types of needle detectors, at the same detection height, the sensitivity is increased by 10%. 4. Automatic detection, automatic induction, automatic stop when no detection is needed, 0-10 sensitivity adjustment, when there is a broken needle, the conveyor belt automatically stops and returns backwards. 5. With a counting function, it can count the number of qualified or unqualified products. 6. It has two alarm modes: sound effect and light alarm. 7. Luxurious appearance, novel style, time-saving and power-saving, simple operation Rapid PCR detection,Rapid Detection Rapid Detection PCR Kit Viral Antigen Detection Jiangsu iiLO Biotechnology Co., Ltd. , https://www.iilogene.com
Thermal sterilization technology
The use of heat to kill harmful microorganisms in food is both an ancient method and a sterilization technique that is extremely important in modern times. In 1804, the Frenchman Appert invented a method of bottling food in boiling water for a period of time to preserve food for a longer period of time. In the 1950s, the French Pasteur demonstrated the microbial spoilage mechanism of food and laid the theoretical foundation for the development of sterilization technology. Food heat sterilization can be divided into low temperature sterilization method, high temperature short time sterilization method and ultra high temperature instant sterilization method.
(1) Low temperature sterilization, also known as pasteurization, is sterilized at 61 degrees Celsius to 63 degrees Celsius / 30 minutes, or 72 degrees Celsius to 75 degrees Celsius / 15 minutes to 20 minutes. Pasteurization technology is to fill the food container and seal it in a packaging container, and keep the temperature below 100 degrees Celsius for a certain period of time to kill the bacteria in the packaging container. Pasteurization can kill most pathogenic bacteria, but the ability to kill non-pathogenic spoilage bacteria and their spores is insufficient. If pasteurization is combined with other storage methods, such as refrigeration, freezing, deoxidation, Packing and matching can meet the requirements of a certain shelf life. Pasteurization technology is mainly used for the sterilization of citrus and apple juice beverages. Because the pH value of juice foods is below 4.5, there is no microbial growth, and the targets of sterilization are yeast, mold and lactobacilli. In addition, pasteurization is also used for the sterilization of jams, canned syrup, beer, canned vegetables, pickles, and the like. Pasteurization has reliable acid resistance for sealed acidic foods. For those low-acid foods that are not resistant to high-humidity treatment, as long as they do not affect consumption habits, pH is often used by adding acid or by means of microbial fermentation to produce acid. In the range of acidic foods, low temperature sterilization can be used to preserve food quality and storage. This method takes a long time and should not be used for heat-sensitive foods. (2) High-temperature short-time sterilization (HTST): The sterilization conditions are 85 ° C to 90 ° C / 3 minutes to 5 minutes, or 95 ° C / 12 minutes, the liquid is heated to nearly 100 ° C, and then quickly cooled to room temperature. This method takes a short time and has a good effect, which is beneficial to product quality. Mainly can kill yeast, mold, lactic acid bacteria and so on. These two methods have the characteristics of stable sterilization effect, simple operation, small equipment investment and long application history. Nowadays, they are widely used in the sterilization of all kinds of canned food, beverage, alcohol, medicine and dairy packaging.
(3) Ultra-high temperature instantaneous sterilization (UHT): It was introduced in 1949 with the appearance of the Stork device, and various types of ultra-high temperature sterilization devices have appeared internationally. Ultra-high temperature short-time sterilization is to heat the food to a high temperature (above 130 degrees Celsius) for sterilization purposes. It can be divided into direct heating and indirect heating. The direct heating method uses high pressure steam to directly spray the food, so that the food is heated up at a rapid rate, reaching 140 degrees Celsius to 160 degrees Celsius in a few seconds, maintaining for a few seconds, then removing the moisture in the vacuum chamber, and then cooling it with a sterile cooler. Room temperature. The indirect heating method is based on the viscosity and particle size of the food, and the plate heat exchanger, the tube heat exchanger, and the scraper heat exchanger are selected. The plate heat exchanger is suitable for liquid foods with a pulp content of no more than 1% to 3%. The tubular heat exchanger has a wide adaptability to the product, and can process liquid foods such as concentrated fruit and vegetable juice with high pulp content. A tubular heat exchanger can be used for products that use a plate heat exchanger to cause coking or blockage, and which have insufficient viscosity to use a scraper heat exchanger. The scraper heat exchanger is equipped with a rotator with blades, which is scraped on the heating surface to push the high-viscosity food forward to achieve the purpose of heat sterilization. The effect of ultra-high temperature instantaneous sterilization is very good, almost reaching or close to the requirement of complete sterilization, and the sterilization time is short, the nutrient destruction in the material is less, the food quality is almost unchanged, and the preservation rate of nutrients is over 92%, production The efficiency is very high, and it is more effective than the other two kinds of heat sterilization methods. The ultra-high temperature sterilization device with the aseptic packaging technology of food has developed rapidly at home and abroad, and has now developed into a high-tech food sterilization technology. At present, this sterilization technology has been widely used for the sterilization of milk, soymilk, wine, juice and various beverages, and the food can be sterilized by immersing it in hot water at this temperature.