The Aseptic Cold Filling of PET Bottle Beverages
With consumers paying more and more attention to the safety and nutrition of beverages, the beverage market is gradually changing from microbiologically insensitive products such as carbonated beverages to microbiologically sensitive products such as milk-containing beverages. The gradual transformation from mainstream packaging to personalized packaging has brought about a change in the whole beverage production process. The driving forces in this process include the mandatory requirements of national food safety regulations; consuming demand of beverages containing natural raw materials; consuming demand of preservative-free drinks; consuming demand with better taste; distribution economics of storage environment conditions requiring long shelf life; lightweight bottles to reduce costs; intensive marketing driving the scheme to expand the scope and catering to the trend of large-capacity PET bottles and so on.Under such conditions, the market ushered in a new beverage production process—aseptic cold filling. Compared with the previous beverage production process, aseptic cold filling adopts advanced and thorough cleaning and sterilization process, fully automatic production process control, perfect quality monitoring system and strict aseptic performance verification procedure, which can minimize the risk of microorganisms and ensure the safety of the produced beverage.
Aseptic Cold-filling refers to filling and sealing sterilized liquid food in sterilized containers at normal temperature under sterile conditions so that the food can be transported and stored at normal temperature during the shelf life. The aseptic cold filling is relative to hot filling. The hot filling process is to fill at the temperature from 85β to 95β, while the aseptic cold filling is to fill liquid at normal temperature. Because the package has reached commercial sterility at first, the packaged food can have a long shelf life without preservatives and refrigeration.
Aseptic cold filling technology is a systematic project to realize a comprehensive technical guarantee for the safety of food and medicine, which integrates many high and new technologies such as optical-mechanical-electrical integration, modern chemistry, physics, microbiology, automatic control, computer communication and so on. The aseptic cold filling production line not only needs to meet the rated capacity but also must pass the sterility assurance level test to verify whether the whole production line meets the requirements of commercial sterility. The aseptic process, which fully reflects the ability to produce sterile products by the aseptic process in the whole production process, needs to be verified from the following aspects: dust particle detection, dyeing test of filling environment, settling bacteria and floating bacteria detection, smearing test, sterilization strength test of filling environment, sterilization strength test of packaging materials, water-in-water test, LG culture medium test, batch production test of low acid products, etc. There are many variables introduced by the aseptic production process, such as the design of the production area and its equipment layout, environmental conditions during production, pollution conditions of all production-related equipment and materials, personnel operation and hygiene conditions, etc. Each link is crucial to the quality of the final product. Once the microbial contamination problem is found, the flora analysis can be carried out by the limited detection method of various microorganisms, and finally, the problem point of the production line can be found.
Status of aseptic cold filling technology
The foreign manufacturers of the PET aseptic production line include Crance, Sidel, Geiger Bogoma, Shibuya from Japan, etc. The domestic manufacturers include Le Hui, Xinmei Star, Langfang Baiguan, tech-long, Puhuasheng, Maticline, Topper Bottlingfilling, etc. The productivity of foreign manufacturers can generally reach 48000 BPH. Shibuya can reach 72000 BPH, and the mechanical efficiency is over 90% with a higher energy utilization rate and equipment running stably. The pass rate of their sterility verification is high. The sterility assurance level is higher. The aseptic period of low acid products can reach 72 hours, and that of high acid products can reach 120h hours. The development level of domestic aseptic lines is uneven. At present, only the aseptic lines of Le Hui and Xinmei Star have a capacity of 30000BPH and can pass the aseptic verification. Other manufacturers generally have a capacity between 18,000 and 24,000 BPH. The aseptic period of similar products is shorter than that of foreign countries, which consumes a lot of energy and chemicals. The domestic aseptic line also has the problem of a high mechanical failure rate. However, foreign production line equipment has high one-time investment, high maintenance cost and long after-sales service period.
Sterile materials obtained from domestic PET aseptic cold filling production lines are sterilized by UHT. Generally, the sterile filling space is cleaned and sterilized by COP/SOP first. Then the 100-class requirements of the filling environment are met by HEPA filters and fans, and the regional pressure difference is formed by the waste gas tower so that the pressure in the sterile area is the highest to isolate the external pollution. The sterile pipeline system is cleaned by CIP first, and sterilization depends on the actual situation of the pipeline. PAA disinfectant method is used at normal pressure, and steam method and superheated water valve are used for a closed pipeline. The sterile packaging container was sprayed with PAA solution on the empty PET bottle, and the bottle cap was soaked or washed to sterilize.
The advanced technology of aseptic cold filling
1. Dry sterilization
Sidel integrated PredisTM solution and its latest SensofillFma aseptic filling technology into a device that integrates bottle blowing, filling and capping, and manufactured the Combi PredisTM Fma aseptic filling machine. In Contiform AseptBloc of Crance, the bottle blank is heated in an infrared oven, then treated with gaseous hydrogen peroxide in a sterilization unit, and then directly enters the aseptic design blow molding unit. The container is blow molded under aseptic conditions. The bottle is filled in a sterile filling machine, and the bottle cap is sealed. The principle of dry sterilization technology for bottle blanks used by Sidel and Crance is that hydrogen peroxide steam is used to dry sterilize bottle blanks at the entrance of the heating furnace of the bottle blowing machine. Sterilization of small bottle blanks with a smooth inner wall is more effective and simple than that of irregular bottles, with few residues, which are generally less than 0.5mg/kg. In addition, the aseptic filling system using this technology also has the advantages of energy-saving, smaller floor space, and can be used for filling light bottles. Because hydrogen peroxide steam is used for dry sterilization of bottle blanks, chemicals and water are not needed, so the use of chemicals and water is greatly reduced. Under the normal use condition of equipment, 200 to 300 cubic meters of water and 150 to 200 liters of chemicals can be saved every day, and no sewage is generated.
2. Low-speed linear filling technology
In the design process of the low-speed solution of Combi PredisTM/CapdisTM FMa of Sidel, the linear design is used, based on the mature sterilization technology of dry bottles and caps, which integrates bottle blowing, filling and capping. It is suitable for sterilization of all kinds of bottles and caps, reducing the floor space of equipment, and can be easily embedded into new or existing factories with ultra-small floor space. Before the new beverage products are put into the market on a large scale, the beverage manufacturers usually make small-scale production first, so as to test the market of these products and observe the reaction of consumers, and then make large-scale production. These high-end products targeted at market segments must be produced on low-speed production lines. At the same time, in the regional market where the demand for products is small, low-speed production is also a practical solution.
Current research on aseptic cold filling
1. Combined sterilization
The combination of various sterilization methods can achieve a good sterilization effect. For example, UV alone is used to sterilize PET bottle caps. Due to the complexity of the inner and outer surface structure of PET bottle caps, the sterilization effect is general. Research results show that the combination of low-concentration hydrogen peroxide solution and high-intensity ultraviolet irradiation will produce an amazing sterilization effect. Compared with the original sterilization schemes of hydrogen peroxide solution+hot air and hydrogen peroxide solution+high intensity ultraviolet, the sterilization system of PET bottle cap researched by Liu Fengchen and others have improved the sterilization mechanism and significantly increased the sterilization intensity. At the same time, the evaporation of hot air and ultraviolet radiation can enhance the sterilization effect, effectively promote the decomposition of hydrogen peroxide, so that there is no hydrogen peroxide residue on the surface of the bottle cap, thus avoiding the effects on beverage taste and drinkers’ health.
2. Electron beam irradiation sterilization
Compared with traditional food preservation methods, electron beam irradiation has no problems such as radioactive pollution and pesticide residues in agriculture and animals, and it saves energy and has particularly obvious advantages. Electron beam irradiation technology uses low-energy or high-energy electron beam rays (electron beams below 10MeV) generated by electron accelerators to destroy DNA in living biological cells by direct action of high-energy pulses or radiolysis of small molecules and water substances by indirect action, forming active free radicals such as -OH and -H, which interact with nuclear substances and generate a cross-linking reaction. At present, many foreign manufacturers have used electron beam irradiation technology to sterilize empty PET bottles and achieved good results. The domestic Xinmei Star has also produced a prototype, and the specific usage is unknown. The reason for electron beam irradiation technology is that the penetration ability of electron beam is weak, and there is a problem in sterilizing the thick bottle mouth of PET empty bottles.
In recent years, the worldwide decline of environmental quality and the increase of people's living pressure brings about a sub-health state increasing for more and more people day by day. At the same time, with the continuous improvement of living standards, people are paying more and more attention to personal health problems. Benefiting from China's huge population base, the rapid growth of functional drinks and vegetable protein drinks will be worth looking forward to. China's functional beverage market has developed rapidly in recent years, with a growth rate of 17.4% in 2014 and a market capacity of 10.91 billion liters. In the five years from 2010 to 2014, the average growth rate of the industry reached 28.9%. It is estimated that the industry will reach 25.457 billion liters by 2019. Plant protein drinks are becoming hot in the beverage market, attracting consumers holding to the concepts of "natural" and "healthy". The increase in beverage consumption will directly lead to an increase in sales of the beverage production line. The aseptic cold filling production line has a wide application range, especially the heat-sensitive neutral products, which will be the best choice. The customers of aseptic cold filling PET bottles generally pursue easy-to-use equipment, safety and reliability, space-saving, energy-saving and emission reduction, high performance and low cost. These requirements will lead the sterile line of PET bottles to the following aspects:
1. Develop towards high-tech integration and high reliability.
In order to meet the safety requirements of products, every subsystem of the system itself contains the achievements of new technologies, new materials and new processes. In order to meet the requirements of high reliability, every subsystem should be integrated into modern quality from design to manufacturing, from operation experiment to operation monitoring, as well as information feedback and compensation correction should be integrated into the modern quality concept to achieve the unity of inherent reliability and operational reliability of the equipment.
2. Developing and extending the concept and requirements of sterility to the application fields of many industries is the outcome of medical development.
With the development of modern microbiology and applied sterilization technology, human beings have a new understanding and control means to kill all pathogenic microorganisms and non-pathogenic microorganisms including bacterial spores. Commercial sterility, as a technical index to evaluate food safety, is recognized by relevant industries and markets.
3. Aseptic packaging equipment is developing to a single high-speed type.
The development of aseptic packaging equipment belongs to the high-end products in packaging machinery in terms of technical content and technical index requirements. For users, this technology and capital-intensive equipment positioning must aim at improving production efficiency, which is different from the development of modern packaging machinery towards multi-function and single high-speed polarization. From the technical level, the development of high-reliability equipment to multi-function will mean that many problems to be solved in engineering technology will appear, which will increase the technical difficulty.
4. Develop in the direction of optimizing cost performance with technological innovation.
Although aseptic packaging has many advantages, its expensive equipment has discouraged many enterprises. Domestic enterprises should promote the healthy development of the aseptic packaging industry. They should provide the market with equipment at a moderate price at a reasonable cost to boost the consumer market. Therefore, technological innovation should be adopted, and the technical strategy of integration and breakthrough should be realized.