Effect of gas nanobubbles on the efficacy of peracetic acid and chlorine against Escherichia coli and Listeria monocytogenes

Primary Author: Arshdeep Singh

Faculty Sponsor: Minto Michael


Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman




Nanobubbles are defined as fine bubbles with diameter varying from 20 to 200 nm with distinctive surfactant properties because of their small size. Nanobubbles are proven effective in irrigation systems, fisheries, wastewater treatments and dentistry. This research was conducted to study the impact of gas nanobubbles on the efficacy of commonly used antimicrobials in food industry. This study was conducted as a completely randomized block design (three replications). Air, CO2 and N2 were used to generate nanobubbles in water. Peracetic acid and chlorine were used to make the nanobubble-antimicrobial solutions and were tested against Escherichia coli O157:H7 and Listeria monocytogenes. Antimicrobials mixed with water without any gas acted as controls. Nine-milliliter of antimicrobial solutions were taken into individual test tubes and inoculated with 1 ml of individual microbial inoculum. After the holding time of 1.5 and 3 min, 1 ml of the sample was taken, neutralized with Dey-Engley broth, and plated on brain heart infusion agar. pH and Eh of antimicrobial solutions were measured before and after the addition of master inoculum. After 3 min for E. coli, CO2 nanobubbles with chlorine was the most effective treatment with 6.4 log reductions as compared to 4.2 log reductions in control. For L. monocytogenes, CO2 nanobubbles with peracetic acid was most lethal treatment with 4.6 log reductions compared to 1.9 log reduction in control. This study demonstrated that efficacy of various antimicrobials can be increased by incorporating gas nanobubbles. Further, this method can be tested against other pathogens in different food matrices.