Preparation and antibacterial activity of chitosan-silver nanoparticles for application in preservation of minced meat

In recent years, the development of efficient and green route to synthesis metal nanoparticles has gained considerable attention in various areas of nanotechnology. Among metal nanoparticles, silver nanoparticles (AgNPs) have attracted much interest because of their potential antimicrobial agents and they are widely applied in many biological and medical fields. With respect to Ag-based nanocomposites, chitosan-silver nanoparticles (Ch-AgNPs) represent an emerging group of bio-nanostructured hybrid materials due to their biocompatibility and biodegradability. Ch is considered a non-toxic biopolymer, as well as its antimicrobial and antifungal activities against a wide range of microorganisms. Colloidal AgNPs were prepared by chemical reduction of silver ions in the presence of Ch giving Ch-AgNPs. Physiochemical characterizations were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), and zeta potential. In vitro antibacterial activity was evaluated against Escherichia coli and Salmonella typhimurium using nutrient agar dilution method. The in vivo antibacterial activity was also tested against E. coli in minced meat under aerobic conditions at 4 °C for 10 days. In addition, different biochemical parameters were determined in minced meat samples. The colloidal AgNPs formed in situ by chemical reduction of Ag ions in the presence of Ch and showed a good stability. SEM and XRD confirmed the formation of nanoparticles. Zeta potential value was decreased by increase the ratio of Ag and was found to be − 0.225, − 0.193, and − 0.0695 mV for Ag ratio 0.1, 0.2, and 0.35, respectively. The in vitro antibacterial activity of Ch and Ch-AgNPs against E. coli and S. typhimurium reveal that the E. coli was more susceptible to these products than S. typhimurium and Ch-AgNPs have more influence with increasing of the silver concentrations. The in vivo antibacterial activity against E. coli in minced meat samples showed that the effect of Ch-AgNPs was a concentration dependent and greater compared with either controls or Ch alone. The results suggest that Ch-AgNPs could be used in food preservation as antimicrobial agents and for shelf-life extension. However, further toxicological studies on mammals are needed.