Aseptic packaging in the food processing industry : different sterilization techniques
Hydrogen peroxide is used to clean and disinfect packages in contact with food products. Its aseptic properties are also invaluable in the sterilization of drink packs (milk, fruit juice, etc.).
In food industry, hydrogen peroxide is used in aseptic packaging machines for disinfection. The packages are then filled with liquid. For this application, 35% hydrogen peroxide is commonly used. Heating of hydrogen peroxide improves its efficiency. It can also be activated with an ultra-violet treatment.
Disinfecting treatments with hydrogen peroxide are odorless and the excess peroxide is decomposed when drying with hot air. Therefore, in this process a rinsing step is not necessary, which is a major advantage for food processing.
Two different techniques are used to apply hydrogen peroxide on the surface of the packaging:
- Spraying of H2O2
- Soaking in a bath of H2O2
Each type of treatment requires a grade of hydrogen peroxide with specific characteristics. Our different Valsterane® food grades have been customized in order to fulfill these specific needs.
Sterilization by H2O2 spraying
This technique is used for the disinfection of “pre-shaped” packaging. Different machines are currently using this process:
- machines for the filling of prefolded "bricks"
- machines for the filling of plastic bottles
- machines for the filling of small plastic packaging
In this type of machine, hydrogen peroxide is sprayed or vaporized at high temperature: 120°C to 250°C. During operation, some deposits can remain in the heating system and may plug the spray nozzles. Therefore, it is absolutely necessary to use a grade of hydrogen peroxide with a dry residue as low as possible. Valsterane® ASG is the grade with the lowest dry residue of our range. Consequently, it is recommended for most of spray machines. However, under certain conditions a more stable hydrogen peroxide is needed in which case Valsterane® FG or AG is recommended.
Sterilization by soaking in a bath of H2O2
In this case, the packaging material is disinfected in an H2O2 bath, before processing it in its final shape. Hydrogen peroxide bath is commonly heated between 45°C and 80°C.
Two opposite phenomena have an influence on the behavior of the bath:
- Evaporation of water, which increases the peroxide concentration of the bath.
- Decomposition of hydrogen peroxide, which is catalyzed by impurities coming from the packaging material and accumulating in the bath. Decomposition is also increased when hydrogen peroxide is heated.
Therefore, stabilization of hydrogen peroxide is a key factor. A too highly stabilized product will induce an increase of peroxide concentration in the bath. At the opposite, if the stabilization of the product is too low, a quick decrease of the concentration of H2O2 will be observed.
Valsterane® AG has been especially designed for bath type machines. Due to the low dry residue of this grade, formation of deposits on rollers decreases and it is possible to reduce the frequency of cleaning and maintenance operations. In some specific cases, Valsterane® ASG is recommended. It has been designed in order to decrease the plugging of spray nozzles used during the start-up of these machines.
Our team is at your disposal to provide any assistance you may require. Do not hesitate to contact us.