Original scientific paper
Direct and indirect plasma yeast sterilization
Nasser N. Morgan
; Physics Department, Faculty of Science (male), Al-Azhar University, Nasr city, Cairo, Egypt
Asem Metawa
; Physics Department, Faculty of Science (male), Al-Azhar University, Nasr city, Cairo, Egypt
Abdou A. Garamoon
; Center of Plasma Technology, Al-Azhar University, Nasr city, Cairo, Egypt
Abstract
Atmospheric-pressure parallel-plate dielectric barrier discharge has been designed for sterilization of Saccharomyces Cerevisiae and Candida yeasts. Oxygen has been used as the input working gas. The output gas after discharge operation was a mixture of both ozone and oxygen, with concentration that depends on the applied voltage between the electrodes, gap space and gas flow rate. Sterilization process has been done in two ways, by direct exposure to oxygen plasma inside the discharge cell and by indirect exposure to the plasma. Survivor curves, and scanning and transmission electron microscope were used to study the inactivation kinetics and morphology of the yeast surface before and after sterilization. It has been found that the indirect sterilization causes yeast inactivation in a short time, less than three minutes, while the direct sterilization took place in a longer time, more than ten minutes.
Keywords
atmospheric pressure discharge in oxygen; sterilization of yeast; exposure inside the discharge cell; indirect exposure; survivor curves; inactivation kinetics
Hrčak ID:
302737
URI
Publication date:
2.5.2010.
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