Aseptic packing is a food production practice where bacteria and viruses are eliminated from the product and prevented from entering during packaging. It is a common way to prepare and package food and can benefit food safety and product shelf-life. Aseptic packaging also presents unique cleaning considerations.

Aseptic packaging is an operation that produces a commercially sterile food product. A product produced under aseptic conditions does not require refrigeration and can have a shelf life of six months to a year. Examples of products that can be manufactured in an aseptic process include milk, flavored milk, fruit juices and canned fruit. The operation reduces food safety risks by producing a sterile product free of viable microorganisms, including spoilage organisms and pathogens. It allows consumers to have highly nutritional products with longer shelf-lives than conventionally processed and packaged products.

An aseptic filling process is similar to most other food production processes with the receiving, storage and blending of ingredients. However, the aseptic process becomes unique at the pasteurizer. The pasteurizer in most aseptic filling plants is an ultra-high temperature (UHT) processing system. A UHT system uses temperature, usually over 275 degrees Fahrenheit / 135 degrees Celsius, and time, usually over two seconds, to sterilize the food product. The time and temperature combination helps achieve the sterilization needed for each product. Every part of the production line from the UHT hold tube to final product packaging must always remain sterile. If there is a break in sterility, the system must shut down and be brought back to sterile conditions before production of an aseptic product can resume. This results in a loss of production time, which decreases revenue.

After the pasteurizer, the product usually moves to a sterile holding tank, which is often sterilized with steam, and then to the filler equipment. Depending on process configuration, the sterilized product may also move directly to aseptic fillers for filling. During aseptic filling, both the machine and the package must be sterilized using steam or chemicals. The filler is in a sterile zone and must stay and operate in sterile conditions. In addition, all transfer lines between the pasteurizer, sterile holding tank and filler must also be sterilized. Similar to the rest of the aseptic process, if the sterile zone is compromised, production will cease until the area can be cleaned and brought back to aseptic condition again. 

Aseptic filling systems can be difficult to clean and most are clean-in-place (CIP). These filling systems also tend to have a higher cost associated with cleaning than traditional CIP systems due to need for increased chemical usage, longer cleaning and sterilization time, and the inability to reuse wash solutions.

The pasteurizer is designed to have low product flow rates to increase the time the product is in the holding tubes to achieve sterilization. Due to the high heat and low product flow, these systems accumulate burned-on soils, which are difficult to remove. Removal of burned-on soils in an aseptic system typically requires twice the amount of caustic than is used in a traditional CIP system. During a production run, an aseptic system can operate anywhere from 24 to 120 hours before cleaning and sterilization. It takes three to four hours to clean a typical aseptic system (Full CIP), then two to three hours to sterilize and bring them back online. The time spent cleaning and sterilizing an aseptic system is lost production time.

To extend production time between a system Full CIP and sterilization, an aseptic intermediate clean (AIC) is performed. AICs are performed during production, on average, every eight hours, which increase the system’s chemical consumption. AICs usually require a two to three percent caustic flush of the system to help remove soils and gross contamination. The system must stay sterile during an AIC to continue running products on the system.

Cleaning solutions are not reused in aseptic systems because they contain too many solids to reuse and lose their cleaning capacity after a single use. Another reason cleaning solutions are not reused is for allergen control. Since the solutions contain a high level of solids, it is possible to transfer allergens, or redistribute them, through reuse. Not being able to reuse wash solutions increases chemical cost as fresh solutions are need for each cleaning cycle.

In LA, Ecolab offers programs and solutions to help maintain and optimize aseptic packaging processes. A robust cleaner, such as Ecolab’s AC-SEEC, provides better cleaning capabilities than a commodity caustic. AC-SEEC aids in dispersing the tough-to-remove burnt on soils commonly found in an aseptic system. AC-SEEC can be used for both Full CIP and AIC cleaning regimes. Additionally, Ecolab offers enhanced removal of burnt soils using Exelerate HS-I to expedite cleaning cycle during Full CIPs. Use of Exelerate HS-I with AC-SEEC during Full CIP can penetrate tenacious soils on heated process equipment when used as a pretreatment to cleaning.

Ecolab also offers 3D TRASAR™ CIP, a diagnostic tool that verifies every CIP wash cycle. It also will send alerts if it identifies any deviations in the wash cycle. It helps to optimize CIP programs, improve overall efficiency, and lower the total cost of operation.

Ecolab has in-depth training and experience in cleaning aseptic systems and can recommend solutions and CIP parameters for optimal cleaning. In addition, the company provides a team of technical service experts – TSS (SEALS) – that can troubleshoot cleaning and shelf-life issues for aseptic packaging systems.

An optimized aseptic packaging system will decrease system downtime and the total cost of operation, helping to increase production and revenue.
 
Dr. Jeremy Adler is an Ecolab senior research, development & engineering program leader for the food and beverage industry.