Investigation of antibacterial activity of ZnO nanoparticles suspension containing citric acid against Salmonella typhimurium in mango and carrot juice

Abstract

Nanoparticles (NPs) are increasingly recognized as their usage in biological applications including nanomedicine and food safety. The objective of this experiment was to determine the effect of ZnO NPs and citric acid on the survival of Salmonella typhimurium inoculated on to mango juice and carrot juice. Antibacterial activities of different concentrations (0, 1, 2, 4, 6, 8, 10 mM) of zinc oxide (ZnO) suspen- sion containing 1% citric acid were tested against the Salmonella typhimurium inoculated on to culture media by spot on the lawn meth- od and culture turbidity as a qualitative measure of the cell growth. Results manifested more inhibitory effect of ZnO in liquid medium than the solid culture against Salmonella typhimurium. These data suggested that the antibacterial activity of ZnO was concentration de- pendent, which was previously confirmed by the agar diffusion test. ZnO NPs were more effective in initial reduction of Salmonella typhimurium. Results demonstrated that ZnO NPs suspensions containing citric acid had synergic effect against studied bacteria in me- dia. Citric acid %1 dilution in concentrations of 10 2 , 10 4 , 10 6 and 10 8 in mango and carrot juice, which is show the highest antimicrobial effect in concenteration 6 mM and 8 mM dilution of the 10 6 and 10 8 . The effect of zinc nano oxide synergic and citric acid %1 has stronger antimicrobial effect in the face with net citric acid %1.