Working principle and key steps of aseptic cold filling
The production process is an extremely complex system engineering, and every step is crucial.
1. Sterilization and cooling of materials
The material is heated to high temperature (such as 105-137 ℃) in a very short period of time (such as 3-15 seconds) through the UHT (Ultra High Temperature Instant Sterilization) system, killing all microorganisms.
After sterilization, it is immediately cooled to room temperature (25-30 ℃) through a plate heat exchanger, and then sent to a sterile filling valve for filling.
2. Sterilization of packaging containers (bottles/caps)
This is one of the core technical difficulties. The bottle and lid are sterilized separately.
Sterilization of bottles: Chemical sterilization is usually used.
Hydrogen peroxide (H ₂ O ₂) spray+sterile hot air drying is the most popular method.
Step: Spray a certain concentration of food grade hydrogen peroxide mist into the bottle to evenly cover the inner wall; Then dry it with high-temperature sterile air, thoroughly decomposing the residual H ₂ O ₂ (generating harmless water and oxygen) while ensuring the sterility and absence of residue in the bottle.
Sterilization of bottle cap: chemical methods are also used, such as hydrogen peroxide immersion, spray or ultraviolet radiation.
3. Creation and maintenance of sterile environment
The entire filling area is a sealed and isolated 'sterile chamber'.
The cabin is filled with sterile air filtered by HEPA (High Efficiency Air Filter) or ULPA (Ultra High Efficiency Air Filter) and maintained at a certain positive pressure to prevent external carrier air from entering.
All equipment surfaces, pipelines, filling valves, etc. must undergo SIP (in-situ sterilization) procedures before production, typically using high-temperature steam or chemical reagents for thorough sterilization.
4. Aseptic filling and sealing
The cooled sterile material is injected into sterilized bottles through a sterile filling valve in an absolutely sterile environment.
The filling valve is precisely designed to ensure no leakage and foam and prevent any secondary pollution.
After filling, immediately seal with sterilized bottle caps to form a sealed sterile product.