In vitro antibacterial activity of gelatin-nanochitosan films incorporated with Zataria multiflora Boiss essential oil and its influence on microbial, chemical, and sensorial properties of chicken breast meat during refrigerated storage

Fresh proteinaceous products with animal origin have a short shelf life. Therefore, this study was done to evaluate the effects of novel films based on the combination of gelatin and nanochitosan incorporated with different concentrations of Zataria multiflora Boiss. essential oil (ZMEO) (0, 0.3, 0.6 and 0.9 % v/v) against two food borne pathogens including Listeria monocytogenes and Salmonella Typhimurium. Afterwards, the effect of films on the microbial, chemical, and organoleptic properties of chicken breast meat was evaluated during refrigerated storage for a period of 14 days. Based on the in vitro findings, the pure gelatin-nanochitosan (GNC) film or GNC film containing different concentration of ZMEO had antibacterial activity against L. monocytogenes, whilst only GNC films containing 0.6 or 0.9 % ZMEO showed antibacterial activity against S. Typhimurium. Also, results showed that the microbial population of chicken breast meat wrapped with GNC films containing ZMEO decreased at least 2 log CFU/g compared to control (P < 0.05). The final total volatile base nitrogen (TVB-N) value for the control sample was 37.52 mg/100 g, whilst the TVB-N values for samples wrapped with GNC films containing ZMEO evermore remained below 25 mg/100 g during the study. At the end of the study, the peroxide values (PV) of control samples reached 8.42 meq/1000 g of lipid, while the values for the wrapped samples remained below 6.52 meq/1000 g of lipid. In conclusion, GNC films containing 0.9 % ZMEO extended the shelf life of chicken breast meat during refrigerated storage for at least 14 days.