Helium dielectric barrier discharge-cold plasma treatment for microbiological safety and preservation of onion powder

Abstract

Efficacy of dielectric barrier discharge-cold plasma treatment (DBD-CPT) for microbial decontamination of onion powder was evaluated. Onion powder, inoculated with Escherichia coli O157:H7, Salmonella Enteritidis, or Listeria monocytogenes, was treated with helium DBD-CPT. DBD-CPT (9 kV, 20 min) inhibited E. coli O157:H7, S. Enteritidis, and L. monocytogenes by 1.4±0.5, 2.3±0.3, and 1.2±0.0 log CFU/cm2, respectively. The inactivation levels of E. coli O157:H7, S. Enteritidis and L. monocytogenes increased by 2.2±0.1, 2.5±0.1 and 1.9±0.3 log CFU/cm2, respectively, as water activity increased from 0.4 to 0.8, and increased by 2.3±0.4, 2.1±0.1 and 1.6±0.1 log CFU/cm2, respectively, as the particle size increased from 0.3 to 1.0 cm2. Neither the ascorbic acid and quercetin concentrations nor the color of onion powder was changed by DBD-CPT (p>0.05). These results demonstrate the potential for application of DBD-CPT in improving microbiological safety of onion powder while preserving the physicochemical properties.