Aseptic filling systems generally combine several elements into a single, integrated production line. This integrated approach helps to ensure microbiological safety throughout the process from initial treatment to the sealing of the finished product. The steps included in an integrated aseptic filling line typically include:
1. Thermal treatment
Although in theory this can be any thermal treatment that reduces harmful bacteria (pasteurization, sterilization or cooking), in practice the types of product that are most likely to benefit from aseptic filling are those that are pasteurized or sterilized. This step usually comprises a suitable tubular heat exchanger.
2. Cooling (where necessary)
Depending on the product, the production process and the packaging used, it may be necessary to cool the product following pasteurization or sterilization. In some situations, such as the production of cooked items like soups and sauces, this step may form the first part of the integrated aseptic line, receiving hot cooked product from elsewhere in the factory. In such cases another heat exchanger will be used. If cooling the product is likely to increase its viscosity, then a scraped-surface unit may be used.
3. Sterilization of the packaging
Prior to filling, packaging is normally sterilized using thermal or chemical methods such as peroxyactic acid or hydrogen peroxide, although in many production environments the packaging is supplied pre-sterilized in aseptic packaging that can be put into the filling line without contamination. However the packaging is sterilized, it is vital that aseptic conditions are maintained between sterilization and sealing, and this is another reason for adopting an integrated aseptic processing solution.
4. Filling and sealing under aseptic conditions
There are numerous systems of aseptic filler on the market, but all try to balance speed, accuracy of operation and flexibility of filling (for example, working with different products and containers), while maintaining the microbial integrity of the product and the sterility of the containers — including suitable cleani-in-place (CIP) systems before, during and after production.
Depending on the product and how it is packaged, filling may be based on weight or volume, and appropriate sensors (such as weigh cells of flow meters) and control systems will be included in the filler machinery.
Once filled, there are many ways that aseptic packaging can be sealed — from screw-capping bottles to heat-sealing pouches or putting lids on bulk containers. These mechanisms may also include some form of tamper-evident system to alert customers or consumers if the pack has been opened since filling.
