Investigation of the practicability of low-pressure microwave plasmas in the sterilisation of food packaging materials at industrial level

Abstract

Experiments on laboratory scale carried out by use of different microwave-driven plasma sources proved that low-pressure plasmas represent an excellent means to efficiently sterilise materials for all kind of applications. Based on experimental results obtained for four different test spores, more detailed experiments on Bacillus subtilis with initial contaminations between 106 and 107 spores and varying spore densities were carried out showing the adaptability of the process parameters microwave power, continuous wave and pulsed power supply, and distance between plasma source and substrate to the individual requirements of the aspired sterilisation process. Spore reduction kinetics reproduced by a low-pressure microwave plasma source designed for industrial applications demonstrated the easy scalability of this plasma sterilisation technique.