The effect of high-power ultrasound and gas phase plasma treatment on Aspergillus spp. and Penicillium spp. count in pure culture.

Abstract

The aim of this study was to investigate and compare two nonthermal techniques in the inactivation of moulds. High power ultrasound (20kHz) and nonthermal gas phase plasma treatments were studied in the inactivation of selected moulds. Aspergillus spp. and Penicillium spp. were chosen as the most common mould present in or on food. Experimental design was introduced to establish and optimize working variables. For high power ultrasound, the greatest reduction of moulds (indicated by the total removal of viable cells) was obtained after ultrasound treatments at 60°C (thermosonication) for 6 and 9min (power applied, 20-39W). For plasma treatment, the greatest inactivation of moulds was observed for the longest treatment time (5min) and lowest sample volume (2ml), (AP12, AP13, PP12 and PP13). The great amount of applied energy required for achieving a partial log reduction in viable cells is the limiting factor for using high-power ultrasound. However, both treatment methods could be combined in the future to produce beneficial outcomes. This study deals with nonthermal food processing techniques and the results and findings present in this study are the root for further prospective studies. The food industry is looking for nonthermal methods that will enable food preservation, reduce deterioration of food compounds and structure and prolong food shelf life.