Abstract:
Milk is an important source of nutrients for humans and animals. But it is a perishable food
that can be spoiled easily and also becomes an important vehicle for transmission of
pathogenic microorganisms to human beings. The main goal of this study was to preserve
raw goat milk by keeping its quality using the lactoperoxidase system without using the
refrigeration system which in effect to deliver safe milk to consumers and to maximize the
income by minimizing loss of milk due to spoilage. The composition analysis of raw goat milk
and the effects of process parameters on the activation of lactoperoxidase system were also
investigated. The lactoperoxidase system was activated by increasing the concentration of
sodium thiocyanate and hydrogen peroxide reacting with each other to yield antibacterial
compound. The experiment was designed by design expert software 11.00 using central
composite design to evaluate the effect of process variables on the growth of total coliform
count. The minimum growth of total coliform count 2.658 log CFU/ml were found at the
optimal condition of 25 oC temperature, 4hr time, 29.98 PPM of sodium thiocyanate and 16.6
PPM of hydrogen peroxide. The process variables, had a significant (p < 0.05) effects on the
growth of total coliform count. The physiochemical characterization (protein content, fat
content, lactose content, total solids, moisture content and ash content) of the preserved milk
under optimal state were found to be 3.84%, 5.61%, 4.68%, 14.98%, 85.02% and 0.85%
respectively.
Microbiological analysis and physicochemical characterization of the raw and preserved
goat milk was analyzed using Minitab 17 version. Therefore the lactoperoxidase system does
not induce any significant adverse effects on the physicochemical characteristics of raw goat
milk. Activation of the lactoperoxidase system can keep goats’ milk fresh for up to 10 hr when
stored at 250C.
