T HE antibacterial activity of nanoparticles and essential oil were tested against S.typhimurium, E. coli, S. aureus and B.subtilis using agar disc diffusion assays. Essential oil and nanoparticles inhibited all tested microorganisms with different concentration against S. aureus, B. subtilis, S. typhimurium and E. coli respectively. Silver and chitosan nanoparticles showed a lower inhibition for all of the tested microorganisms compared to essential oil. The present study characterized of AgNPs (~16.77nm) and ChNPs (~20.25nm) using (TEM) and GC/MS to measure chemical components of cumin and marjoram essential oils. Gamma.-Terpinene accounts for 25.54 % of total chemical components in cumin essential oil and Bis (2-ethylhexyl) phthalate accounts for 24.48 % of total chemical components in marjoram essential oil. Fish fillets inoculated were analyzed for B. cereus and E. coli during cryopreservation. Results demonstrate that cumin essential oil at 500 ppm is more active than marjoram essential oil at 500 ppm, ChNPs 1% and AgNPs 40µg/ml respectively when compared to the control. These results revealed by increased storage time were decreased microbial growth in fish fillets inoculated with B.cereus were more active than fish fillets inoculated with E. coli.Therefore, the application of nanoparticles and essential oil has a good potential to be antimicrobial activities for various food applications.