Azadeh Khiabani - Corresponding Author , PhD Student in Research Institute of Food Science and Technology (RIFST), Mashhad, Iran
Ali Mohamadi Sani - Young researchers and Elite Club, Quchan Banch, Islamic Azad University, Quchan, Iran
Monir-sadat Shakeri - Department of Food Biotechnology, Research Institute of Food Science and Technology (RIFST), Mashhad, Iran

This study was carried out to evaluate the in vitro antibacterial activities of nanofluid based on Ziziphora tenuior essential oil and Zinc oxide (ZnO) nanoparticles against pathogenic bacteria in food, including two gram-negative and two gram-positive bacteria. The agar disk diffusion and micro-dilution methods were used to study the antibacterial activity. Results revealed that the highest zone of inhibition (19-23 mm) for the Nanofluid containing the ZnO (0.75 v/v-EO,125 ppm-NP) compared to the control (without ZnO - 0.75 v/v EO). Minimum inhibitory concentration (MIC) against Bacillus cereus, Staphylococcus aureus, Salmonella entrica and Escherchia coli was determined respectively 0.015 %v/v-EO - 2.6 ppm-NP, 0.019 %v/v-EO - 3.3 ppm-NP, 0.061 %v/v-EO - 10.54 ppm-NP, 0.093 %v/v-EO - 15.62 ppm-NP. Minimum bactericidal concentration (MBC) against the mentioned bacteria were repectively 0.046 %v/v-EO - 8 ppm-NP, 0.061 %v/v-EO - 10.54 ppm-NP, 0.124 %v/v-EO - 20.83 ppm-NP, 0.187 %v/v-EO - 31.25 ppm-NP. Bacillus cereus was respectively the most sensitivite specie while Escherchia coli was the least sensitivite specie. ZnO nano-particles improved the antibacterial activity of the essential oil quite effectively, which shows the potent application of the particles in different systems based on the essential oils like food packaging, food systems and pharmaceutical.

Antibacterial activity, Essential Oil, Ziziphora tenuior, Zinc oxide, Nanofluid, nanoparticles