A cleaner type of filling
David Strauss of Krones discusses cold-aseptic beverage filling with PET-Asept
Firstly we must answer the question that was posed at the Fresenius Congress early in June 2003, as to whether aseptic filling was merely a "machinery trend" or a "necessity for surviving on the market", there was a clear answer from the expert Michael Braitinger: "Consumers are demanding flawless, unadulterated products. Aseptic filling as a physical process provides precisely the quality improvement that customers want". His vision: 1. "Cold-aseptics are the only way to get back to products that are not only just food, but nourishing food; 2. Cold-aseptics have to involve the elimination of aids like Velcorin or other process additives; 3. Cold-aseptics are the only way to enhance the quality of our diet." The approach adopted for cold-aseptics by German company Krones, Neutraubling/Germany, has proved to be a good choice. When installing new aseptic bottling lines, the world's beverage industry puts definite trust in Krones' technology: More than a third of PET-Asept lines ordered worldwide in 2003 came from the company. This is firstly attributable to purposeful design enhancement of the unique isolator system with a minimised cleanroom, and secondly to the skills and expertise of a dedicated aseptic team, which look after new aseptic lines from quotation formulation all the way through to validation. The PET-Asept process is mainly used for sensitive beverages, both still and carbonated. The new technology is also being employed for milk-based mixed beverages and for the first time with UHT milk.
Cold-aseptics beat hot filling For filling PET bottles with sensitive beverages, there are two safe technologies from a microbiological viewpoint: hot filling and cold-aseptics. Both of them, naturally, have their advantages and disadvantages. In cold-aseptic filling, the product, the container and the closure are sterilised separately, and brought together under aseptic conditions – without using preservatives or thermal treatment during or after filling. With hot filling, the product, the bottle and the closure are heated up during the process, and thus sterilised. In addition to technological aspects, it is the cost factor in particular which plays a major role in capital investment decisions. The beverage bottlers' preference is emerging clearly: the demand for cold-aseptics shows a substantial rise. Cold-aseptics require a higher outlay on machinery. The capital investment costs involved are concomitantly greater. For hot filling in PET bottles, by contrast, it is the more cost-intensive hotfill bottle that shows up in the running costs. These material costs for the PET preform are the crucial factor in comparing the long-term operator costs. The bottom line is that hot filling, when all factors are taken into account, is approximately 20% more expensive than the up to date option of cold-aseptic PET bottling. What is more, for conventional PET bottle there are almost no restrictions on bottle design in regard to marketing considerations.
New isolator technology The PET-Asept process from Krones provides sterile beverage filling to a maximised level of technological distinction. The PET-Asept line consists of the following modules: steriliser, rinser, filler and closer, which are linked together by neck-handling starwheels in a BLOC configuration. The company has been purposefully enhancing the design of its cold-aseptic filling technology, and has thus simplified handling for the users while assuring maximised levels of dependability. In the new version, the size of the cleanroom has been reduced to the absolute minimum, thus helping to cut the costs involved. Only the actual path of the bottles is located inside what is called an isolator, a leak-proof compartment meticulously separated from the surrounding atmosphere. Two-stage filters remove the germs from the inflowing air, creating a sterile atmosphere inside the isolator itself. The aseptic compartment is kept at a slight overpressure compared to its surroundings, which prevents germs entering via the airlocks. At relevant points, operators can intervene in the compartment using gloves fixed in the isolator's wall. The machines' drives, plus the electric and pneumatic supply lines, are located outside the aseptic zone for easy access. The individual modules are mounted on gable-type front tables, whose roof-shaped construction makes them extremely easy to clean.
A persuasive concept After entering the aseptic zone, the PET bottles pass through the steriliser where they are treated with disinfectant. When sterilisation has been completed, the disinfectant solution has to be removed from the bottles again before they are passed to the filler. In the rinser, each bottle is rinsed out with sterile water and flushed with sterile air via a two-component nozzle. The sterilised bottles now enter the filler. "The company's concept of the smallest possible cleanroom with an isolator is a very persuasive one", emphasised Dr Norbert Bühler, Plant Manager of Pomdor's Sursee facility in Switzerland. Pomdor has been using the PET-Asept variant since early 2003, enabling the firm to bottle both still and carbonated fruit juices, plus fruit-juice-based beverages and lemonades or syrup. Special attention was paid to the bottle closer. Germ formation, germ entrainment and product contamination from the sealing heads and their drive units, normally located above the bottles, are critical issues, particularly whilst the bottles are still open before the sealing function and during transport of the closures. With a completely fresh concept for the closer, the company has thus found an answer to the stringent requirements applying for aseptic filling. In this aseptic solution, the cam support and the sealing head have been relocated for optimised microbiological safety, and are now underneath the bottle mouth, inwardly offset from the bottle axis. By restricting the machine components to the absolutely necessary minimum above the bottle path, this entirely innovative concept enables the microbiological framework conditions to be optimised for truly aseptic closing.
Both still and carbonated "One of the line's huge advantages is that we can run both still and carbonated products on it", says Frank Jehring, the General Manager of Fruchtquell Dodow, a subsidiary of riha (the Richard Hartinger Beverage Group). "Most of the lines on the market at present can either do one or the other". The line is primarily intended for bottling still fruit-juice-based beverages, ACE and multi-vitamin drinks, and ice tea, but Fruchtquell is also considering carbonated spritzers in PET. For bottling carbonated beverages, a special version of the filling system has been chosen: the VODM-C-PET-Asept filler. This design operates with valves for filling still and carbonated products, and provides for pressed-on filling in a counter-pressure process. This filler has no internals in the zones coming into contact with the product. In addition, the system can be simply and effectively cleaned in a CIP process. Before the bottles reach the closer, a nitrogen droppler sprays inert gas into the bottleneck, so as to prevent oxygen pick-up in the product. "In our sector, which is characterised by excess capacities, competition on quality is naturally quite fierce", says Frank Jehring. "We are convinced that PET packaging as such will be very well received in the future. And we are seeing that the topics of full juice in PET, and the elimination of all preservatives, will be offering niches on both the German and international markets. The microbiological results and cost-efficiency figures we're getting with the new PET-Asept line give us plenty of reasons for optimism".
Continuous output assured Experience has shown that only a holistically integrated system will assure proper functioning of a cold-aseptic filling process. In addition to the actual aseptic BLOC, the system also has to optimally incorporate the product process technology of the flash pasteuriser or ultra-high-temperature system (UHT) and the mixer, with a sterile buffer tank and aseptic valves, plus automatic media preparation of disinfectant solution for bottles and closures, sterile water, sterile air, food-quality steam and sterile inert gas. The company supplies the PET-Asept filling BLOC as a turnkey job, with all the relevant peripherals, reverse-osmosis water treatment, UHT system for water sterilisation, cleaning agent and disinfectant supply, nitrogen droppler and closure feed.
