Researchers say plasma technology is effective sterilizer
Peter Muranyi from the Department of Food Technology at the Fraunhofer Institute of Process Engineering and Packaging (IVV) spoke about the technology at the Anuga FoodTec trade show in Cologne last week.
He said that the cascaded dielectric barrier discharge (CDBD) plasma system that the research team aims to incorporate into filling equipment was developed by the Fraunhofer Institute for Laser Technology in an earlier research project funded by the German ministry for education and research (BMBF).
Muranyi said that CBDB technology is a further development of a conventional barrier discharge whereby the replacement of the dielectric by a flat excimer lamp increases the homogeneity of the discharge and the inactivation efficiency of the UV radiation.
Fast, safe method
He told FoodProductionDaily.com that sterilization using plasma technology is currently an active field of research because gas plasma allows fast and safe sterilization of packaging materials such as bottles, lids and films without adversely affecting the main properties of the materials.
Muranyi claims that results from tests evaluating the use of the CDBD technology with food related polymers like PET, PE or PS did not show significant modifications of parameters like the sealing strength, gas permeability or friction coefficient of the polymers.
Removal of chemicals
Low temperature plasma has the potential to replace or complement current sterilization methods for packaging materials that are chemical reliant such as methods that combine hydrogen peroxide or peracetic acid with moderate heat, he continued.
CDBD technology, explained Muranyi, works at room temperature with common process gases like air or argon, and thus eliminates the need to use potentially harmful chemicals.
Bacteria inhibition
“Tests on a PET film with the CDBD, equipped with a XeBr-Excimer and laboratory air as process gas, have shown a high microbicidal effect against a wide range of different test strains. In the case of B. atrophaeus or Cl. botulinum endospores, for example, a count reduction of nearly 6 log10 within one second was achieved,” he added.
He added that in comparison to glass aseptic or thermal sterilization methods, the CDBD system uses less energy and is more economical.
While the system is designed to sterilise flat packaging materials, Muranyi maintains the CDBD system could be further developed, through the addition of special electrodes, to enable the decontamination of three-dimensional objects such as bottles and cups.
