In specific food applications practically sterile powders are required. In many cases conventional methods for sterilisation, such as autoclaving fail due to sensibility of powders to heat, humidity and / or mechanical stress.

Cold atmospheric plasma provides an alternative mechanism of inactivation of microorganisms on food powders or surfaces of equipment, packaging etc. Low temperatures combined with short treatment times have been found to inactivate even most heat resistant microbial spores.

A capacitive coupled - low pressure, a dielectric barrier discharge (DBD) and a surface micro discharge (SMD) plasma device was used in order to characterise kinetics of inactivation of microbial spores, the impact of various process parameters such as power input, process time or surface charge with contaminants and to develop a machine concept for decontamination of food powders.

One of the devices applied currently in a laboratory scale is supposed to have the potential to be applied on continuous flowing, dry powdered food. For decontamination of powder of less sensibility to humidity a vacuum-steam-vacuum fluidized bed process including pilot plant scale equipment was developed by the same group and in cooperation with the Swiss Federal Institute of Technology Zurich (Hörmansperger, J.T., Buchmann, L., Merz, S., Schmitt, R., Beyrer, M., Windhab E.J., Microbial decontamination of porous model food powders by Vacuum-Steam-Vacuum treatment, Innovative Food Science and Emerging Technologies (2016).


Michael Beyrer

HES-SO Rectorate
Route de Moutier 14
2800 - Delémont
T +41 58 900 00 00 - F +41 58 900 00 01