Modification of bacterial structures by a low-temperature gas plasma and influence on packaging material

To investigate the effect of a cascaded dielectric barrier discharge (CDBD) treatment on the biological structure of a selected bacterium and on the properties of different polymer films.

Inactivation kinetics were measured using air as the process gas and using Bacillus atrophaeus spores and vegetative cells, which had been homogeneously distributed on a surface. The changes to the outer coats and the DNA of the endospores and cells after plasma treatment were determined using biomolecular and chemical methods. The experiments showed that damage to the DNA molecules and changes in the cell walls can be observed as a consequence of the CDBD treatment. Furthermore, the influence of the plasma treatment on the properties of various polymer films was investigated using a variety of test methods. Except the sealing strength where a slight decrease was observed (max. 20%), no negative changes of the material properties have occurred.

CDBD treatment can affect the DNA of spores and cells, depending on the treatment time. At the same time, practically relevant inactivation rates on packaging materials were observed, without any significant changes to the material properties.

Knowledge about CDBD mechanisms was acquired from a biological point of view, and the suitability of the method for treating polymer films was demonstrated.