Bacteria, spores, fungi and yeasts. In the new microbiology lab at Plasmatreat's head office in Steinhagen, researchers Cathrin Heißenberg, M. Sc. biotechnology and Daniel Haße, M. Sc. biochemistry are investigating options for using atmospheric pressure plasma to disinfect these microorganisms. They are focusing their attention on packaging materials for food and pharmaceutical products, and medical devices and instruments.
Harmful germs can be transferred to packaging via people, raw materials or air, from where they may then contaminate the product. In industrial production facilities even the tiniest amounts of contamination can cause significant problems and even lead to product spoilage. Plastic packaging such as yoghurt pots, screw caps or drink bottles must therefore be sterilized before contact with the product in order to guarantee product quality even for prolonged periods.
The thermoplastics generally used to make this type of packaging are heat sensitive. Often it is not possible to sterilize their surface using hot saturated steam or dry heat, so instead chemical disinfectants are used such as hydrogen peroxide or peracetic acid. The storage and use of these aggressive and corrosive disinfectants is frequently problematic and furthermore, residual disinfectant in the product poses a potential risk to consumers.
With the aid of atmospheric pressure plasma, packaging materials can be sterilized quickly without using chemicals. “In our microbiological plasma laboratory we work predominantly with dielectric barrier discharge (DBD), a process which primarily produces reactive oxygen species,” explains Cathrin Heißenberg. She continues: “These species irreversibly damage cell membranes and other subcomponents within the microorganisms, for example by oxidizing lipids.” One advantage of the DBD plasma process is its low temperature increase during processing so that even thermolabile materials can be treated at temperatures below 40° C.
In addition to its new research area of microbiology, Research and Development at Plasmatreat also encompasses the fields of physical principles, electronics development and process engineering. The Department works closely with national and international research institutes and universities on a range of joint research projects.