Microbial Decontamination of Gwamegi (Semi-dried Pacific Saury) Using Corona Discharge Plasma Jet, Including Physicochemical and Sensory Evaluation

The use of corona discharge plasma jet (CDPJ) for the improvement of hygienic quality of Gwamegi was investigated. Microbial contaminants, namely aerobic, marine bacteria, coliforms, Staphylococcus aureus, and molds and yeasts, were detected in Gwamegi samples. The CDPJ generated using 20 kV DC voltage and at 58 kHz frequency was used for the decontamination treatment (1–10 min). The bacterial contaminants and molds and yeasts were inactivated in the range of 1.9–3.3 and 3.2 log CFU/g, respectively. The inactivation pattern fitted well to the pseudo-first-order model. The CDPJ treatment for 10 min did not exert significant changes (p > 0.05) in pH, moisture content, water activity, peroxide value, acid value, and volatile basic nitrogen content of Gwamegi as compared to controls. On the contrary, significant changes (p < 0.05) in color and thiobarbituric acid reactive substance levels were noted. However, the CDPJ-treated Gwamegi displayed better sensory properties than controls in terms of appearance, visual color, and flavor.