Impacts of Dielectric Barrier Discharge on Microbial Decontamination of Crystal Sugar for Using in Pharmaceutical Products

The effects of Dielectric Barrier Discharge (DBD) on crystal-sugar contaminated with Geobacillus  stearothermophilus   and Aspergillus niger was studied with combined variables of power (5–15 w), time (2-10 min), and voltage (15-22 kV). The total microbial loads of Gs (9×105) and An (9×104 CFU/g) loads were destructed (P ≤ 0.05) when the voltage and power were 22 Kv and ≥ 5 W. Additionally, their death values (D) were equal and below 1.18 min, respectively. Results showed that increasing voltage had at least 70% more effects on Gs sterilization than the time and power of DBD. Although the cold plasma has substantial destructive effects on the  cell membranes, DNA, and protein of microrganisms, Scanning Electron Microscopy (SEM) of A. niger,  and G.  stearothermophilus confirmed the disinfection process by changes happened in their sizes, configurations, and spores due to the cold plasma process. The DBD method (a non-thermal procedure) can be applied as a new antimicrobial practice to fully sterilized the purified crystal sugar and make it completely appropriate for pharmaceutical and baby food industry.