Antimicrobial and antioxidant effects of nisin Z and sodium benzoate in vacuum packed Caspian Kutum (Rutilus frisii) fillet stored at 4◦C

This study was done to evaluate the antimicrobial and antioxidant effects of nisin Z (0.02 %) and sodium benzoate (1.5 and 2.5 %) in vacuum packed Caspian Kutum (Rutilus frisii) fillet stored at 4°C. Microbial changes [aerobic plate counts (APC), psychrotrophic counts (PTC) and lactic acid bacteria] and chemical indices [peroxide value and total volatile basic nitrogen (TVB-N)] were determined in days 0, 4, 8, 12 and 16. Results showed that PV and TVB-N in control samples (the sample dipped in prechilled distilled water) were deteriorated after 12 days compared to preserved samples which were acceptable after 16 days. Microbial tests indicated that control samples contained APC and PTC bacteria in day 16 more than standard limit, whereas treatment samples were in the acceptable range. In case of lactic acid bacteria, after 16 days, all samples were in the acceptable range. Results of chemical and microbial analysis showed that simultaneous use of nisin Z and sodium benzoate could increase the shelf life of vacuum packed R. frisii.