Gliding Arc Plasma Discharge Conditions on Microbial, Physicochemical, and Sensory Properties of Shrimp ( Litopenaeus vannamei ): In Vivo and In Vitro Studies

The aim of this study was to determine the optimal conditions for gliding arc plasma using a response surface methodology and consider a low total mesophilic aerobic bacteria (TMAB) count, peroxide value (PV), color differences (Δ E ), and appropriate sensory properties of stored Pacific white shrimp (PWS; Litopenaeus vannamei ). A Box–Behnken design was used with three independent variables: argon gas (50–100%), treatment time (2–10 min), and sample distance (3–7 cm). Argon gas and treatment time significantly influenced TMAB, PV, ΔE, and sensory properties of the PWS, while sample distance had less effect. A high concentration (100%) of argon gas in the plasma caused a decrease in TMAB (1.2 CFU/g) compared to low concentrations (50%) of argon gas (5.41 CFU/ml). Also, high concentrations of argon gas cause a decrease in PV and an enhancement in Δ E and in the sensory properties of the shrimp. The results show that the use of 94.15% argon gas for 7.10 min with a sample distance of 6.54 cm provides optional gliding arc plasma conditions of 76.3% desirability. Using these numbers while maintaining desirable properties in stored PWS caused an identical reduction of Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , and Proteus mirabilis under in vitro and in vivo conditions. In optimal conditions, concentrations of H 2 O 2 , nitrate, and nitrite in plasma-activated water (PAW) measured were 0.92 mM, 19.42 μM, and 9.62 μM respectively. Scanning electron microscopy (SEM) analysis demonstrated that optimized plasma can destroy the cells of Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa , and Proteus mirabilis bacteria .