Inactivation of Escherichia coli and Bacillus cereus in Myungran jeotgal (Korean traditional salted pollack roe) using floating electrode-dielectric barrier discharge plasma

Abstract

Nonthermal plasma technology has garnered significant attention for its food preservation capabilities. However, the applicability of floating electrode–dielectric barrier discharge (FE-DBD) plasma in this regard has not been explored. Therefore, the effects of FE-DBD plasma (1.1 kV, 43 kHz, N 2 1.5 m/s, and 1–90 min) on Escherichia coli and Bacillus cereus and on the quality characteristics (pH, Hunter colors) of Myungran jeotgal (a traditional Korean salted fermented pollack roe) were investigated. When FE-DBD plasma was applied for 1, 5, 10, 20, 30, 60, and 90 min, E. coli and B. cereus contents decreased by 0.03–1.35 log and 0.04–1.02 log colony-forming unit (CFU)/g, respectively. After a treatment of 90 min, both bacterial species showed a reduction of >1 log CFU/g. When the first-order kinetic model was applied, E. coli showed a D -value of 65.37 ( R 2 = 0.99) and B. cereus showed a D -value of 88.50 ( R 2 = 0.98). After FE-DBD plasma treatment, the pH significantly decreased from 5.87 to 5.75, lightness (L*) decreased, and redness (a*) significantly increased ( p < .05). However, the yellowness (b*) was not significantly different ( p > .05). These changes can be attributed not to the direct effects of the FE-DBD plasma but rather to an increase in the surface moisture caused by the internal moisture diffusion during treatment under ambient conditions and to the associated quality changes occurring during the treatment process. Further studies incorporating temperature control during treatment would suggest that FE-DBD plasma could be utilized as an effective nonthermal sterilization technology for M. jeotgal .