Effects on the Fresh-Keeping of the Raw Milk by Exogenous Activating Lactoperoxidase System

The aim of the research was to contrast the effect of different concentration Lactoperoxidase System(LPS) by exogenous activating on the fresh-keeping of the raw milk.12,15 and 20 mg·L~(1) sodium thiocyanate were added respectively into the raw milk of the experimental Group A,Group B and Group C in proper order,then 9 μL·L~(-1) hydrogen peroxide was added respectively into each of the experimental groups.The results showed that different concentration of LPS had different effects of keeping freshness.Milk fresh period of Group A,Group B and Group C was respectively 17,20.5 and 21 hours,prolonged correspondingly the preservative time by 4,8 and 8.5 hours,and improved the hygienic grade by about 1 or 2 grade at the same time compared with the control raw milk.These facts suggested that fresh-keeping effect of Group B and Group C was better than that of Group A.On the other hand,because the salt thiocyanate of raw milk in Group C exceeded the limits,the best effect was produced by Group B among the three groups.