Study on presciption of coating edible preservative for cheese

To study and develop an edible preservation film,the antibacterial property of the base liquid mixture adding the inhibiting components of natamycin and lysozyme were tested. The base liquid was composed of caseinate sodium,and chitosan and glycerol. The test bacteria were E.coli,Staphylococcus aureus,Pseudomonas fluorescens,yeast and mold. The result showed that the antibacterial effect of natamycin on mold and yeast was enhanced with the increase of its dosage,and there were significant differences between different dosage( p <0.05).Inihibiting effect of natamycin on Staphylococcus aureus,Pseudomonas fluorescens was first increased and then decreased and the effect on E.coli showed no significant difference among different amount( p > 0.05).The inhibitory effect of lysozyme had a significant effect on yeast( p < 0.05),but the inhibition zone of other bacteria were less than 12 mm.Response surface analysis was employed to optimize parameters of the prescription of the base liquid with blend of natamycin and lysozyme.The evaluating index was the increment of absorbance. The results revealed that the optimum additive amount of natamycin and lysozyme was 0.07 g /100 m L base liquid and1 g /100 m L base liquid. At this dose,the absorbance increment of the base liquid reached a minimum value.The result also showed that there were significant interaction effects between chitosan and natamycin,as well as between chitosan and lysozyme( p < 0.05),wheras the interaction effects between natamycin and lysozyme was not significant( p > 0.05),and the diameter of the inhibition zone of E.coli,Staphylococcus aureus,Pseudomonas,yeast and mold were 13.67,14.33,15.66,18.00,17.76 mm in this ratio respectively.