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The most important application of nanotechnology in the food industry is the production of active packaging with antimicrobial properties, packaging with special mechanical properties in terms of gas and heat exchange and nanosensors in intelligent packaging. The aim of this study was to investigate the antimicrobial effect of silver and copper nanocomposites on Escherichia coli and Staphylococcus aureus. Nanocomposites containing silver and copper nanoparticles in 1, 3, 5 and 7% percentages were produced by extrusion method and were subjected to nanometric analysis. Then, the antimicrobial test of nanocomposites was performed on commercial strains of Staphylococcus aureus and Escherichia coli by measuring the inhibition of growth in the culture medium.  The data showed that the size of copper and silver nanoparticles was in the range of 20 to 50 nm and the dispersion of nanoparticles on the surface of nanocomposites was uniform with high purity. Antimicrobial test of nanocomposites showed that with increasing the percentage of nanoparticles, the diameter of the growth inhibition of nanocomposites increased significantly and the rate of inhibition of growth of silver nanoparticles was higher than copper (p≤0.05).  Staphylococcus aureus was more sensitive to copper and silver nanoparticles than Escherichia coli (p≤0.05). The results of the present study showed that silver and copper nanocomposites with high antimicrobial properties can be used for food packaging.

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Plant extracts and nanoparticles prepared from them due to their antimicrobial and antioxidant properties can be used to increase the shelf life of meat. In the present study, the biodegradable film of polylactic acid containing silver nanoparticles synthesized from Satureja rechingeri extract on the physicochemical and microbial properties of chicken fillet at refrigerated temperature was investigated. So that the control sample (code 1), chicken fillet coated with biodegradable film of polylactic acid (code 2), chicken fillet coated with biodegradable film of polylactic acid containing Satureja rechingeri extract (code 3) and the Chicken fillet coated with biodegradable polylactic acid film containing silver nanoparticles synthesized from Satureja rechingeri extract (code 4) at 4°C in chemical, microbial and sensory properties at intervals of 0, 3, 7 and 14 The days were examined. The results showed that the mean diameter of the growth inhibition zone against Staphylococcus aureus and Escherichia coli bacteria for Satureja rechingeri extract containing silver nanoparticles was significantly higher than Satureja rechingeri extract (p≤0.05). In all the studied days except the first day, the lowest pH of thiobarbituric acid belonged to sample 4 (p≤0.05). Also, on the third and seventh days, the highest L* color component belonged to sample 4 (p≤0.05). On all the examined days, except on the first day, the lowest population of mesophilic bacteria, psychrophilic bacteria, coliform, Staphylococcus aureus, mold and yeast, and mold and yeast, as well as the highest score of all sensory factors (odor, color, texture, overall acceptance) belonged to sample 4 (p≤0.05).Sample 4 was selected as the superior treatment for higher sensory score and more desirable microbial properties.