## 3 Results and Discussion  
### Determination of ADCP Treatment Conditions  
To determine ADCP treatment conditions, _Salmonella_ inactivation rate was evaluated under voltages of 22, 23, and 24 kV, for treatment times of 2.0, 2.5, and 3.0 min (Table 1). Increasing treatment voltage from 22 kV to 24 kV led to a significant increase in the _Salmonella_ inactivation level (\(p<0.05\)), suggesting that treatment voltage is a critical variable in ADCP treatment for packaged meat products. [PERSON] et al. reviewed studies that investigated the decontamination of foods and food simulants using different in-package cold plasma configurations. They concluded that increasing treatment time (plasma generation time) and voltage have a positive impact on reducing bacterial populations [7]. Increased efficacy of microbial inactivation may be associated with an increase in antimicrobial substances in the packages subjected to ADCP treatment. [PERSON] et al. demonstrated that ADCP treatment of raw chicken fillet packaged in a polymeric tray at 80 kV significantly increased the formation of ozone, a common component existing in packages treated with ADCP and a well-known antimicrobial agent, compared with 55 kV at 200 to 950 rpm [15].  
_Salmonella_ inactivation levels following ADCP treatment at 24 kV, for 2.0, 2.5 and 3.0 min, were 0.90 \(\pm\) 0.07, 1.00 \(\pm\) 0.01 and 1.45 \(\pm\) 0.05 log CFU/cube, respectively; treatment time of 3.0 min produced the highest inactivation level (\(p<0.05\)). [PERSON] et al. [1] reported that ADCP treatment at 100 kV for 1, 3, and 5 min was applied to fresh chicken breast samples, where the highest inactivation (approximately 1.5 log CFU/g reduction) in the natural microflora of chicken was achieved within 5 min of treatment and 24 h of storage [1]. Furthermore, they demonstrated that treatment time exerted a significant effect (\(p<0.05\)) on the decrease in population for mesophiles, psychrotrophs, and _Enterobacteriaceae_[1]. [PERSON] et al. used dielectric barrier discharge cold plasma treatment on packaged fish samples in PET containers, and reported that increasing treatment time led to increased concentrations of antimicrobial ozone and nitrogen oxides (NO\({}_{2}\), NO\({}_{3}\), N\({}_{2}\)O\({}_{4}\)) [26]. The increase in _Salmonella_ inactivation levels with treatment time suggests that treatment time was considered as another important variable affecting ADCP treatment. The treatment voltage of 24 kV and 3 min, which resulted in the highest _Salmonella_ inactivation (1.45 \(\pm\) 0.05 log CFU/cube), were used for ADCP treatment in all subsequent experiments. Treatment times above 3.0 min were not investigated in this study because, in food production lines, post-packaging sterilization time is mostly limited to a few minutes [27].  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{2}{c}{**Conditions**} & \multicolumn{2}{c}{_Salmonella_} & **Microbial Reduction** \\ \hline
**Treatment Voltage** & **Treatment Time** & **(log CFU/cube)** & **(log CFU/cube)** \\ \hline
22 kV & \multirow{2}{*}{3 min} & 4.42 \(\pm\) 0.05 & 0.62 \(\pm\) 0.02 c \\ \cline{3-4}
23 kV & & 3.96 \(\pm\) 0.07 & 1.08 \(\pm\) 0.03 b \\ \hline  & 2 min & 4.14 \(\pm\) 0.09 & 0.90 \(\pm\) 0.07 b \\ \cline{2-4}
24 kV & 2.5 min & 4.04 \(\pm\) 0.13 & 1.00 \(\pm\) 0.01 b \\ \cline{2-4}
3 min & 3.59 \(\pm\) 0.06 & 1.45 \(\pm\) 0.05 a \\ \hline \hline \end{tabular}  
* The number of _Salmonella_ in ADCP-untreated chicken breast cubes: 5.04 \(\pm\) 0.13 log CFU/cube; values are meaning mean and standard deviations (n = 4); different letters mean significant differences between data in the same column (\(p<0.05\)).  
\end{table}
Table 1: Effects of treatment voltage and time on the inactivation of _Salmonella_ in chicken breast cubes by in-package atmospheric dielectric barrier discharge cold plasma (ADCP) treatment.