Low-temperature, low-pressure gas plasma application on Aspergillus brasiliensis, Escherichia coli and pistachios
Article first published online: 14 FEB 2014
© 2014 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 116, Issue 5, pages 1137–1148, May 2014
How to Cite
Pignata, C., D'Angelo, D., Basso, D., Cavallero, M.C., Beneventi, S., Tartaro, D., Meineri, V. and Gilli, G. (2014), Low-temperature, low-pressure gas plasma application on Aspergillus brasiliensis, Escherichia coli and pistachios. Journal of Applied Microbiology, 116: 1137–1148. doi: 10.1111/jam.12448
- Issue published online: 11 APR 2014
- Article first published online: 14 FEB 2014
- Accepted manuscript online: 21 JAN 2014 04:16AM EST
- Manuscript Accepted: 9 JAN 2014
- Manuscript Revised: 31 DEC 2013
- Manuscript Received: 4 NOV 2013
- Piedmont Region
- Aspergillus brasiliensis ;
- Escherichia coli ;
- gas plasma;
The aim of this study was to investigate the effect of plasma-enhanced chemical vapour deposition (PECVD) treatment on selected bacteria and spores and to contribute to the understanding of the synergistic effect of UV-directed plasma.
Methods and Results
The experiments were conducted on pure cultures of Aspergillus brasiliensis and Escherichia coli and on naturally contaminated pistachios that were exposed to pure oxygen-, pure argon- and to a mixture of oxygen–argon-generated plasma for different treatment times and at different micro-organism concentrations. Optical emission spectroscopy (OES) measurements were performed to observe the active species in the plasma. After exposure, the effectiveness of decontamination was assessed through microbiological techniques by calculating the growth reduction on a logarithmic scale. A treatment time of 30 min resulted in a 3·5 log reduction of A. brasiliensis using pure oxygen or argon, while treatment times of 5 min, 1 min and 15 s resulted in a 5·4 log reduction using a mixture of argon and oxygen (10 : 1 v/v). Treatment times of 1 min and 30 s resulted in a 4 log reduction of E. coli with oxygen and argon, respectively, which led to a complete elimination of the micro-organisms. Two-log reductions of fungi were achieved for pistachios after a treatment time of 1 min.
These results suggest that this newly designed plasma reactor offers good potential applications for the reduction in micro-organisms on heat-sensitive materials, such as foods. The plasma that was generated with Ar/O2 was more effective than that which was generated with pure oxygen and pure argon.
Significance and Impact of the Study
An improvement in the knowledge about PECVD mechanisms was acquired from the chemical and biological points of view, and the suitability of the method for treating dry food surfaces was demonstrated.