Background and objective: Recently, silver nanoparticles have attracted a growing attention in food processing due to their antimicrobial activities. In this study, antimicrobial effect of silver nanoparticles in rainbow trout fillet packaging's was investigated.

Materials & Methods: Two samples of nanofilms containing silver nanoparticles covered on titanium dioxide were prepared. First, the quality of 3 and 5% nanofilms was assessed by SEM electron microscope. Following the preparation of nanofilms and a bacterial suspension of E.Coli, the antibacterial activity of nanofilms was measured according to 10900 standard. Rainbow trout fillet was packed in nanofilms and stored for 0, 7, 14 and 21 days in a 4°C refrigerator, and total bacterial count was compared with the samples without nanofilms.

Results: The inhibitory effect of 3% and 5% nanofilms on mesophilic bacteria was significant till 7 days, and no considerable change was observed in the following days. The 3% nanofilm had no significant effect on the growth rate of psychrophilic bacteria whereas the effect of 5% nanofilm on the growth rate of pschrophilic bacteria was significant for 7 days.

Conclusion: According to the results, utilization of nanofilm containing silver nanoparticles increases the shelf life of rainbow trout fillet.

Keywords: Nanofilms, Silver nanoparticles, Titatium dioxide, Rainbow trout