PET Asept System D – a basis for filling UHT milk products

Besides proven aseptic filling using the PET-Asept process with peracetic acid (PET-Asept L), Krones offers an alternative called "dry sterilisation" featuring hydrogen peroxide (H₂O₂ ).  The H₂O₂ concept is especially well suited to the dairy industry, where hydrogen peroxide sterilisation constitutes the established process or is requested for certification by the authorities in particular countries.
When certain closures, e.g. sportscaps like push-pull or flip-top closures, are used, H₂O₂ sterilisation likewise offers definite advantages compared to treatment with peracetic acid. One of the salient reasons for using H₂O₂ , however, is the significantly reduced water consumption involved, and the concomitantly downsized amount of effluent. Krones adopts the approach to true dry sterilisation using gaseous H₂O₂ for packing material disinfection. Here the bottles are pre-warmed to the treatment temperature of 50 – 60 °C, then sterilised internally with gaseous hydrogen peroxide, avoiding any condensation.
The attraction of this dry sterilisation process lies in the use of moderate temperatures, which permits the reaction time of gaseous H₂O₂ to be extended almost at will without damaging the PET bottles. There is another crucial advantage to the Krones PET-Asept D System: Now that condensation can be dispensed with, it becomes possible to BLOC-synchronise the blow-moulding machine directly with the Aseptic BLOC.

The Krones H₂O₂ concept achieves the three stipulated goals:

• The sterilisation performance with spray contamination in the bottle is log 5, determined using the count reduction test referenced to spores of Bacillus subtilis (atrophaeus) and Aspergillus niger.
• The residual concentration of H₂O₂ is below 0.5 ppm, in line with the FDA Guideline.
• Container shrinkage is less than 0.5 per cent.