GEA Procomac’s ABF (Aseptic Blow Fill) has successfully passed the LA (Low Acid) microbiological validation making it suitable to fill milk and milk based products.
The ABF consists of a traditional oven, a preform steriliser, a sterile blower and an aseptic filler. The preforms are warmed up in the oven so they arrive already hot in the steriliser where they are sterilised internally and externally by a flow of hydrogen peroxide. Once sterile they enter the sterile area of the blower, are stretch-blown into bottles and then filled in an aseptic filler.
The blower is sterilised using hydrogen peroxide and the sterile environment inside the microbiological isolator is maintained with an overpressure of sterile air.
The high and low-pressure pipelines that supply blowing air to each mould are also sterilised to maintain sterility throughout the system.
During operation, a standard stretch rod moves up and down in a non-sterile environment entering the moulds and touching the preform/bottles. A new system from GEA Procomac includes a magnetic joint that allows movement inside the aseptic housing and makes sure that, after sterilisation with hydrogen peroxide, the stretch rod remains sterile.
Preforms are much thicker and more heat resistant than bottles. Once they are sterile they can be blown without the need for further sterilisation. This allows bottles to be much lighter weight and, therefore reduces PET consumption.
The Low Acid validation was structured to challenge the decontamination capabilities of the machine in different crucial areas:
- In the aseptic blower and internal pipelines by inoculating the biological indicator Bacillus atrophaeus ATCC 9372 in a spot and performing up to six log reductions. The sterile environment after preform sterilisation ensures that they won’t be re-contaminated again before being filled
- On preforms internal and external surfaces inoculating Bacillus atrophaeus ATCC 9372 and performing up to six log reduction. A key feature of the ABF is the simultaneous internal and external sterilization treatment of the preforms, with no risk of cross contamination
- A production test with culture broth was carried out on three batches of 10,000 bottles with zero defects on the 30,000 produced. This is an excellent result compared with the standard for this kind of test of max 1:10.000 defects per batch
The culture broth test is especially important to study the enhanced growth of specific microorganisms that can grow in a LA product. This test provides checks at every step through the aseptic machine, confirming that containers were properly sterilised, the environment was properly sterilised and kept in sterile, and that the right overpressure inside the microbiological isolator was maintained.
