inhibitory effect of nano-gel/emulsion of chitosan coating incorporated with ziziphora clinopodioides essential oil and nisin on escherichia coli o157:h7 inoculated in beef at cold storage condition

Introduction: this study was conducted to evaluate the influence of chitosan nano-gel/emulsion coating functionalized by ziziphora clinopodioides essential oil (zceo) and nisin on growth inhibition of escherichia coli o157: h7 inoculated in beef samples during 16 days in cold storage condition (4˚c). methods: beef sample was divided into six groups after inoculation of e. coli o157:h7. treatments including control (no coating), chitosan 2%, sonicated chitosan 2%, nano-emulsion of chitosan coating containing zceo (0.5%), nano-gel of chitosan coating containing nisin (200 iu/g), nano-emulsion of chitosan coating containing zceo (0.5%) and nisin (200 iu/g) were stored at refrigeration temperature and bacterial count were performed on days: 0, 1, 2, 4, 8, 12 and 16. data were analyzed using repeated measure anova and bonferroni post hoc tests. results: result indicated a significant reduction in e. coli o157:h7 count in all treatments when compared to control group and the highest inhibitory activity was observed in chitosan nano-emulsion coating containing zceo (0.5%) and nisin (200 iu/g). conclusion: accordingly, it is suggested that chitosan nano-emulsion coating with zceo and nisin practically be applied in beef to increase its safety against pathogenic bacteria especially e. coli o157: h7.