The purpose of this study was to determine the effects of plasma treatment on bacteria in liquid phases. We predict that the plasma gas can penetrate the liquid culture media and plasma treatment will efficiently kill the bacteria at unique time and distance parameters. It is also hypothesized that less stringent plasma treatment will negatively affect the growth rate of some species of bacteria and possibly their pathogenicity. The bacteria were exposed to hot and cold plasma at various time lengths and distance parameters. Our results indicated that 2 minutes of hot plasma treatment with the plasma torch 5 cm away from the liquid culture is effective in killing/sterilizing cultures of S. aureus, S. pyogenes, Salmonella spp, N. meningitidis, and E. coli. Five minutes of cold plasma with the probe immersed 1-2 cm inside the liquid culture were needed to kill the bacteria. The portable nonthermal plasma system can be used for infection treatment and wound healing applications affected by the microbes studied in this research.