Antibacterial properties of Zataria multiflora Boiss. essential oil nanoemulsion formed by emulsion phase inversion

This study aimed to investigate preparation of a Zataria multiflora essential oil nanoemulsion and to evaluate its antibacterial against Salmonella Typhimurium and Listeriamonocytogenes. The average particles size of nanoemlusion prepared by inversion phase using tween 20, which measured by dynamic light scattering, was 66.5 nm. The antibacterial activity of nanoemlusion has examined through agar diffusion, vapor-phase diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time kill curves against Salmonella Typhimurium and Listeriamonocytogenes in BHI. The average diameter of the zones of inhibition of nanoemlusion through agar diffusion was 8.3 and 8.54 mm for S. typhimurium and L. monocytogene, respectively. Also, average diameter of the zones of inhibition of nanoemlusion was zero against both bacteria according to vapor-phase diffusion. The results showed that nanoemlusion exhibited MIC and MBC of 5000 µg/ml on S. typhimurium and MIC and MBC of 2500 µg/ml on L. monocytogene. The effect of 10, 100 and 1000-fold diluted nanoemlusion on both bacterial kill in BHI at 0, 15, 30, 45 and 60 minutes and the results showed that in BHI, the 10 and 100 fold-diluted nanoemlusion caused a 6 and 4 log reduction at S. Typhimuriumin 60 min and the 10-fold caused more than 4 log reduction of L. monocytogene. According to the results, it can be concluded that prepared nanoemlusion is suitable antimicrobial solution and by optimizing the process, it can be beneficial to control the bacterial microorganisms of foods.