Since 1961, the world's first hydrogen peroxide sterilized tetra Pak aseptic filling machine was introduced to date, aseptic automatic filling system technology has been developed to the degree of perfection, has become a set of electromechanical integration technology, modernization, physics, microbiology, automation, computer communications and a number of high-tech technology in one of the high-end technology, and with the modern technology with the day-to-day progress of the development. In terms of paper-plastic aseptic packaging machine, there are vertical and horizontal, in-line forming cartons and preformed cartons, packaging forms from the earliest polyhedral packaging to the development of different capacities of the brick carton packaging and roof packaging, style is more innovative and as far as possible to adapt to the consumer's psychology. PET bottles because of the lightweight, transparent, unbreakable, recyclable and rapid development. From the development of hot filling to aseptic filling so that the advantages of PET bottles have been fully exploited, the application of aseptic filling technology to reduce the cost of bottles at the same time more diversified bottle type can be realized from PET raw materials directly into bottles and on-line aseptic filling, so that the overall cost of a further reduction in the advancement of these technologies and microbial fencing system continues to improve, based on the safety, reliability and environmental protection is inseparable.

Liquid food sterilization technology innovation and improvement is an important part of the rapid development of aseptic filling technology and equipment. Fluid control system application of liquid food sterilization time, temperature has been accurate and effective control, thus ensuring the stability and safety of product quality. With people's pursuit of food nutrition and color, aroma and taste, I hope that the commercially available liquid foods, juices, beverages and milk, etc. closer to the original flavor of food and nutrition. Over the years, scientists continue to explore and seek more advanced sterilization methods, which in addition to the classic steam as a heating medium HTST and UHT, microwave sterilization, resistance heating technology, high-voltage sterilization, high-voltage pulsed electric field, radio waves, excited-state ultraviolet pulse sterilization technology and other physical methods of sterilization technology is being studied in-depth, and some have been commercialized. 

Inter-wall UHT system with saturated steam as heat source 

Ultra-high temperature sterilization (UHT) systems are composed of a set of tubular or plate heat exchangers, material tanks, sustaining tubes, superheated water preparation systems, and CIP automatic liquid filling machines. These equipments are connected into an organic whole through pipelines and valves with different performances, and the whole weighing and filling machine is controlled by PLC in order to realize automatic program operation and automatic adjustment of process parameters. The type of sterilizer depends on the type of liquid food. Usually, most of the products with good fluidity adopt plate heat exchanger as sterilizer-cooler. For higher viscosity products, most of the tube heat exchanger is used, and for higher viscosity products, the scraping surface heat exchanger is used. Tube sterilizer has a multi-casing and multi-tube two types, the former is a set of different diameters, with corrugated concentric casing, according to the needs of 3-8 casing can be made, the heat medium and the material heat transfer can be carried out through a heat transfer surface or two heat transfer surface, can realize the countercurrent operation. Multi-tube sterilizer can actually be viewed as a 180 ° bend will be more than shell and tube heat exchanger connected to the heat exchanger irrigation. It is in a larger diameter tube (114-318mm) is loaded with 7-92 φ 19-38mm straight tube, the tube length of 3-6m, can realize the multi-process flow operation, which is currently used more tube sterilizer type. According to the Italian SIG Manzini company, the company cooperated with the University of Parma to study the heat transfer of the bellows and smooth tube structure of the tube sterilizer, that the viscosity of the liquid food, such as milk or juice, when the fluid is in the turbulent or turbulent flow, the fluid in the corrugated tube and smooth tube heating or cooling of the total heat transfer coefficient is close to the fluid in the corrugated tube and cooling the smooth tube is significantly higher than the pressure drop in the corrugated tube smooth tube. The pressure drop of the fluid in the bellows is significantly higher than that in the smooth tube. For the heating and cooling of viscous materials, when the fluid is in the transition flow, the total heat transfer coefficient and pressure drop in the bellows are significantly greater than the smooth tube. 

Radio wave sterilization technology in cooperation with the University of Milan, Italy, radio waves for liquid food heating industrial filling has been put into practical use. ART30 type weighing filling machine has been used for milk and juice sterilization, respectively, with a production capacity of 3300l / h, sterilization temperature of 140 ℃, the radio waves installed power of 100kw, the maximum use of thermal power 75kw (65000kcal/) h). The construction of the whole set of metering filling machine is similar to the traditional UHT system, the material in the material tank is first pumped into the heat recovery filling, and then heated to the set sterilization temperature in the radio wave heating unit, the high temperature material is filled through the maintenance tube, heat recovery meter and cooled to the filling temperature and then sent to the aseptic filling machine for filling.

The filling machine using radio waves with a frequency of 27.12MHZ is treated with liquid food due to the magnetic field so that the polar molecules produce high-frequency vibration soup and warming, the heating time is only 1/100 of the traditional hot water heating. and food contact materials made of polytetrafluoroethylene. The advantage of using radio wave sterilization is that the food is heated evenly, not in the tube wall due to overheating and produce dirt, the flavor of the product is closer to the raw material itself. Radio wave sterilization technology can be used for fruit and vegetable juices, jams, milk and dairy products with lumpy materials, as well as heat-sensitive juices and fruit pulp. 

Microwave Sterilization 

Microwave refers to the frequency of 300MHz ~ 300GHz electromagnetic waves, used in the food industry microwave frequency of 915MHz and 2450MHz. microwave heating of liquid food with polar molecules is the material itself will be microwave energy into the result of thermal energy. Microwave sterilization is not only due to the role of the organism to absorb energy converted into thermal effect, but also with the help of its non-thermal effect. The non-thermal effect of microwaves refers to the organisms in the role of electromagnetic waves do not produce a significant temperature rise, but the normal metabolic function of microbial cells can be interfered with the destruction, inhibition of growth, or even stop growth or death. Microwave can also make the microbial cells of the water activity is reduced, destroying its living environment. Application of microwave can be used than the traditional heating method of lower temperatures to kill microorganisms in the material. 　

Pulsed microwave sterilization is mainly the use of non-thermal effects, the method is:

The use of instantaneous high-power pulsed microwave energy and the average power is very low pulsed microwave sterilization technology, so that the object in a very short period of time by high-energy microwave irradiation so that bacteria and other microorganisms in the extremely high electromagnetic field under the action of the loss of viability so as to achieve the purpose of sterilization and other purposes.

To milliseconds of continuous and stopping time periodically cut off the continuous wave microwave power, so that the cell muscle by the cycle of continuous action, resulting in a resonance state, resulting in bacterial cell membrane vibration breakage caused by bacterial death. 

High-pressure sterilization technology 

High-pressure technology is placed in the liquid medium of food, in the 100-1000MPa pressure for treatment and processing, in the process of food enzymes, proteins and starch and other macromolecular substances inactivation, denaturation and pasting, and at the same time destroy the cell membrane of microorganisms and achieve the purpose of sterilization. High-pressure technology for food sterilization to avoid a series of processing defects brought about by heat treatment sterilization, it will not destroy vitamins, pigments, flavors and make the loss of nutrients, does not produce heat odor, and can effectively save energy. Therefore, since 1986, Japan's Tokyo Metropolitan University Lin Li Maru proposed a high-pressure technology in the application of food research report immediately after the attention of some developed countries, and has made some progress.　

Continuous high-pressure sterilization is the liquid food pumped directly into the pressure vessel, by an isolation plate will be separated from the pressure medium and liquid food, medium pressure transmitted to the product through the partition, after processing the product is pumped into the aseptic tank. In order to prevent contamination, the use of sterile water as a pressure medium, in order to achieve high-pressure sterilization and aseptic liquid metering filling machine continuous operation. 

Aseptic quantitative filling 

There are now over 400 aseptic automatic filling machines for paper-plastic composite packaging in operation across the country. In addition, there are also aseptic liquid weighing and filling machines for large bags of concentrated fruit and vegetable juices or purees, and aseptic metering and filling of composite plastic film packages in operation. 5 aseptic quantitative metering and filling production lines for PET bottles were firstly introduced by Beijing Huiyuan Juice and Tianjin Tingxin Group in 2001 and a total of 17 such production lines have been introduced in the country since then. The introduction of these aseptic quantitative weighing filling production technology and equipment to promote and develop China's beverage industry has played a catalytic role in China's beverage industry, so that the production technology of the beverage industry in China's filling equipment into the international advanced ranks. 　

The form of aseptic quantitative filling machine depends on the packaging materials, in terms of its key technology to achieve aseptic metering liquid filling, a complete performance of aseptic metering liquid filling machine should include the packaging materials sterilization, aseptic liquid food delivery, filling and sealing in an aseptic atmosphere and other metering and automatic filling, in addition to the conditions of CIP and SIP. There are various ways to sterilize paper-plastic packaging materials. Tetra Pak's paper-plastic packaging materials are submerged in a hot hydrogen peroxide solution with a concentration of 35% and then formed into cylindrical rolls, which are sterilized by O3 decomposed by H2O2 under high temperature conditions, and the filling and sealing of materials are completed in rolls filled with O3. PKL's Combi Pack is to fully spray atomized H2O2 inside and outside of the box in the shaped box, and then make the carton sterilized by O3 produced by decomposing H2O2 by hot air. The O3 produced sterilizes the carton and also creates an O3 atmosphere in the small environment where it is filled and sealed. Multi-layer film composite pouches for aseptic metering and weighing filling as large bags are pre-sealed with a plunger-like stopper for the filling port, then irradiated with a sufficient dose of CO60 to kill microorganisms in the pouch, and sterilized, uncapped, filled, and sealed outside of the filling port in the aseptic chamber of the weighing and metering filling machine. Early aseptic chamber is sterilized with halogen or peroxide and other chemicals, but now has most of the saturated steam sterilization, the volume of the aseptic chamber is less than 0.01M3.

The disadvantage of paper-plastic packaging materials is difficult to recycle, if not specifically recycled, the pollution of the environment is self-evident. In recent years, the application of PET (polyethylene terephthalate) bottles in the beverage industry has developed rapidly, and its advantages, in addition to the convenience in terms of consumption can also be realized in the efficient production of bottle making and filling, and the material can be recycled. The key technologies to realize the aseptic weighing and filling of PET bottles are mainly the sterilization of bottles and caps, the maintenance of an aseptic atmosphere in the filling and sealing area, and the weighing and liquid filling machine itself which should meet the requirements for aseptic filling. The main method used for bottle and cap sterilization is the use of chemical agents, the current use of more hydrogen peroxide, peroxyacetic acid and ethylene oxide and so on. When used, it will be warming, atomization, all-round spray to all parts of the bottle, after a certain reaction time and then rinse with sterile water to minimize the chemical residues in the bottle. High-speed PET bottle aseptic weighing and automatic filling is designed as three independent rotary models for sterilizing - rinsing, filling and sealing of bottles, which are connected into a combined machine by a star-shaped rotor and are contained in a huge aseptic chamber, in which the cleanliness of the filling - sealing area is up to grade 100, and the aseptic air flows in the aseptic chamber in a laminar flow from the top to the bottom, which is in the form of positive pressure. At the end of production and before the start-up of the sterile room with foaming disinfectant disinfection. Many companies have made efforts to reduce the aseptic space, such as CASGOOD will be filled valve and bottle transfer channel sheltered in only 9m3 clean area, between the rotary body and static isolation cover with dynamic liquid sealing, to maintain aseptic area of positive pressure operation. The benefits of reducing the sterile zone include lower sterilant usage, saving sterilization time, reducing chemical contamination of operators, and facilitating maintenance of mechanical components outside of the sterile room.