Assessment of nanochitosan packaging containing silver NPs on improving the shelf life of caviar (Acipenser persicus) and evaluation of nanoparticles migration

Nano packaging plays a major role in reducing microbial load and preserving proper quality. The aim of this study was to evaluate antimicrobial characteristics of nanochitosan-silver packaging against both Gram positive and negative microorganism. The total count test was used to measure the antimicrobial effects. Additionally, the minimal inhibitory concentration and minimum fungicidal concentration of nano chitosan were both measured. Finally, the antimicrobial effects of the silver and chitosan nanoparticles were evaluated. Caviar samples were inoculated to Coagulase-positive Staphylococcus aureus, Escherichia coli using 0/5 McFarland standard. Also, Fusarium solani was inoculated to caviar samples using 10⁵ CFU/mL. Samples were checked out in the 1st, 15th, 30th, 60th, and 70th days, respectively. To determine the size and distribution of nanoparticles) NPs), scanning and transmission electron microscopy (SEM&TEM), dynamic light scattering (DLS), and atomic force microscopy (AFM) analyses were used. The images from SEM and TEM were indicative of spherical silver nanoparticles (AgNPs), and the average size of the AgNPs was lower than 100 nm. The average size of chitosan particles was 60–100 nm as revealed by DLS and Zeta potential analyses, and the chitosan nanoparticles were completely homogenous. The results showed that silver and chitosan NPs had significant antibacterial effects compared to blank low-density polyethylene samples (P < 0.05), and reduced the bacterial and fungal loads more than one logarithmic cycle. Migration of nanoparticles was measured using the atomic absorption spectroscopy (AAS), inductively coupled plasma mass spectrometry (ICP-MS). AAS results showed no migration of nanoparticles although, the ICP-MS showed 0/165 ppm from nanopackaging.