Abstract:To improve the bacterial inhibition and physical properties of oriented polypropylene（OPP）/gelatin bilayers for better application in the field of fresh lamb preservation，this study compared the inhibitory effect of 14 essential oils on 19 spoilage bacteria which were isolated from vacuum-packed chilling fresh lamb by inhibition zone experiments.The type of essential oil with the optimal inhibitory effect was selected to make compound.Then，the compound essential oils with gelatin mass of 0%，10%，20%，30%，and 40%were added to the gelatin layer.The most appropriate concentration for compound essential oil addition was determined by the bacteria inhibition，thickness，mechanical properties，color，light transmission rate，water vapor transmission rate，and sensory evaluation of bilayer.The results showed that the optimal antibacterial effect among the 14 essential oils was mustard essential oil，followed by oregano essential oil.It was further determined that the antibacterial effect was better when the volume ratio of mustard essential oils to oregano essential oil was 1∶4.As the concentration of compound essential oil increased，the film thickness，yellowness，and bacterial inhibition increased significantly，whereas elongation at break，light transmission，and sensory acceptance decreased significantly，and tensile strength displayed a trend of first increasing and then decreasing.In conclusion，the volume ratio of mustard essential oils to oregano essential oil was 1∶4，and the OPP/gelatin bilayer with 20% of the compound essential oil concentration was most suitable for vacuum-packed chilling fresh lamb.