SPORE FORMING BACTERIA ISOLATED FROM STERILIZED MILK IN MOSUL MILK PLANT

This study was performed to detect the spore forming bacteria that frequently represent the major bacteria in sterilized milk that might cause milk deterioration. A total of 46 isolates were noticed in sterilized milk produced by the Mosul milk plant through a period of four months (July, August, September and October). These isolated bacteria all belonged to the genus Bacillus which included B.subtilis, B.circulans, B.licheniformis and B.megaterium that represented 52,23,15 and 8% , respectively. The influence of storing process for 4 weeks at 35C on the number of spores and upon the ratio of deteriorated sterilized milk samples revealed that the number of spores increased upon the increase in storage time and ranged from 3-97 spores/ml. and it was also noticed that the percentage of deteriorated milk samples were relatively high, 5% during the third week of storage in August followed by another 5% the next week. While during September, the deterioration took place through the fourth week and had 10% of the stored bottles, whereas no deterioration was observed through both July and October. The acidity levels of sterilized milk were within the normal, 0.18 0.23 % which leads to a conclusion that deterioration due to the proteolysis of milk proteins.