Phosphatase activity levels in pasteurized goats' milk

A study of the effect of pasteurization on goats' milk took place in order to compare the effectiveness of two pasteurization processes (low and high pasteurization) by assessing the procedure microbiologically and biochemically. The results revealed that both pasteurization processes were effective, showing microbial destruction of approximately 100%. With regard to the determination of phosphatase activity to monitor pasteurization, data in both cases were higher than the limit established for a well pasteurized milk, according to the method used. Machine milked milk showing a lower microbial content nearly achieved the standard level by batch pasteurization, 0.75 μg phenol/ml, but 2.5 μg phenol/ml by the high temperature short time (HTST) method. Phosphatase activity levels of 1.8 and 4.3 μg phenol/ml were the mean values obtained for low and high pasteurization respectively. Our results lead to the conclusion that the batch method for pasteurization of goats' milk is more efficient in terms of total bacterial count than the HTST method. Furthermore, the technique used for the determination of phosphatase activity does not seem to be adequate for pasteurization control of goats' milk, since in very rare situations were we able to attain the limit established.