Inactivation and removal of Enterobacter aerogenes biofilm in a model piping system using plasma-activated water (PAW)

Abstract Plasma-activated water (PAW) was explored as a clean-in-place agent for inactivating biofilms of Enterobacter aerogenes on the inner surface of a model piping system. Abilities of PAW or chlorine solution or distilled water to inactivate the biofilm (~1 × 108 CFU/cm2) attached to the pipe inner surface were compared. Distilled water flowing at 0.11 m/s through the piping system reduced the Enterobacter aerogenes counts on the surface by 0.35, 0.2, and 0.2 log CFU/cm2 on the tees, elbows, and tubing, respectively. However, PAW reduced the E. aerogenes counts on tees, elbows, and tubing by 3.0, 3.2, and 3.8 log CFU/cm2, respectively, which were similar to 100-ppm chlorine water. Increasing the flow velocity to 0.22 m/s made only small difference in terms of biofilm removal. The antimicrobial effect of PAW for Enterobacter aerogenes biofilm on the inner surface of a piping system was comparable to 100-ppm of chlorine solution.