Krones' system solution for PET bottled dairy filling

At present, the packaging trend of milk and liquid dairy products clearly points to plastic containers. In terms of production, the market share of plastic bottles now exceeds 30%, but this is only the beginning. In the field of milk and liquid milk products, HDPE bottles are currently mainly used as packaging for products. However, PET bottles are increasingly integrated into this market because they are recognized by dairy companies and consumers. This situation is particularly prominent in foreign countries.

For the packaging process of milk and liquid dairy products, filling is undoubtedly the most critical link. Milk and dairy products with different shelf life put different requirements on filling equipment and peripheral equipment. Krones distinguishes dairy and dairy products into fresh milk products with a shelf life of less than 10 days, refrigerated sales, and long-term shelf-life milk products (ESL milk) with a shelf life of 30 to 60 days (maximum 90 days), as well as those sold at room temperature. Aseptically filled UHT ultra-high temperature instant germicidal products. This article describes some of the system solutions for these different PET bottled dairy fillings.

Fresh milk products

The shelf life of general fresh milk products is less than 10 days, and the bacterial content (after pasteurization at 75° C. for 15-30 seconds) is 3000-7000 colonies/ml.

Fresh milk products can be selected for weighing and volumetric filling machines for filling. The inside and outside surfaces of the container do not require special hygienic measures and do not require special sterilization methods. On the contrary, CIP and SIP internal scrubbing must be performed (CIP: caustic washing 85° C., 20 minutes, pickling 20-60° C., 20 minutes/SIP: 90° C., 30 minutes). It is recommended to use conventional instruments and valves. The material and structure of the screw capping machine must improve the hygienic level and it is recommended to achieve IS0 level 7.

ESL 30 Milk

Krones recommends that the filling machine be equipped with an automatic CIP cleaning cup. The valves can be either seat valves or butterfly valves. Whether the container needs to be treated depends on the original number of bacteria in the container. Krones can assist companies in selecting the right production equipment and can achieve a 42-day shelf life without using any sterilization method.

Krones has developed a balanced approach to the need for sterilization. Bottles and caps are treated the same way. Its purpose is to provide users with good investment/operating costs while ensuring reliable sterilization. In contrast, the peracetic acid baths that are commonly used are used, as well as two-channel or three-channel rinsers using hot peracetic acid. The ESL 30 filling unit is rated at ISO 7 isolation, making this solution even more perfect. All media for sanitation (internal/external) and container sterilization are from the company's health center designed specifically for the ESL 30. In addition to the biological shelf life (<125°C/2-20 seconds), the freshness of the product is also the focus of attention. The product flow is formulated by the dairy company and then Krones implements the production process.

ESL 60 Milk

If you want to ensure that your milk stays in the cold chain for 60 days, you must use a jet-type dual or triple-channel rinser and ensure that the bacterial reduction reaches log3. Sanitary seat valves must be used in areas close to the product; standard valves can be used in other areas that come into contact with the medium. With the peracetic acid soaking tank, the bacterial reduction of the bottle cap is adjusted to log3. It is recommended that process control and production line diagnostic systems be used. Since 60-day shelf life is an important indicator for users, machine and process technology must be certified and tested for acceptance.

The isolation plan suits this higher requirement. The combination of ISO 6 (for filling machines) and ISO 7 (for rinser) ensures that it is not contaminated by ambient air. A Krones sterile water treatment unit (heater) and CIP module provide sterile water for the ESL 60 filling unit during production - for flushing bottles, caps and nozzles, and flushing with high pressure hot water And sterilization maintains internal hygiene. The product processing temperature is in the high temperature zone (<125°C, 2-20 seconds).

ESL 90 milk

The 90-day shelf life ESL 90 milk is a special form that is currently used in the North American market. In ESL 90 milk Bloc filling units, ISO 2 or ISO 5 is used in the isolation compartment and two dual-channel rinsers are configured. The first rinser was flushed with sprayed acetic acid and sterile air. With this configuration, the action time of the sterilizing medium is prolonged.

By properly adjusting the processing parameters (time, concentration), the soaking tank method can also achieve log4 reduction. The media required for sanitary maintenance (internal/external) and container sterilization are provided by the health center. The sterilization process of the filling machine was extended to 125°C for 30 minutes. The preparation of media, such as sterile water, detergents, and bactericides, as well as methods for the sterilization of containers or products, must always refer to aseptic filling.

UHT Instant sterilizing milk

For the UHT Instant sterilizing milk, the highest grade of sterilizing dairy products and packaging, and the shelf life of up to three months, naturally leaving a small space for the choice of equipment. Here, only the PET bottle aseptic filling system (CAF) can be considered for filling aseptic products in a sterile environment. The container delivery can only be bottle necked and the bottle is operated in isolation channels of ISO 6 and ISO 5 sterile grades. The sterilizer uses peracetic acid to sterilize the inside and outside of the bottle and the number of bacteria is reduced by at least log5. The next two-channel rinser removes the sterilizing fluid by spraying with sterile water and sterile air.

For aseptic filling, Krones offers both volumetric filling systems and weighing filling systems. Of course, the internal brushing of the filling machine must use the CIP/SIP method and the caps are sterilized in a peracetic acid bath (bacterial reduction of at least log5). Foam cleaning, sterile water preparation, and the preparation of biocide health centers are all essential, as are the PCS controls for all process steps and the line recording system LDS. All machine methods and quality certifications and audits are also required.

Source: Global corrugated box industry