Bacterial Content and Keeping Quality of Butter after Removal from Storage

Abstract

Summay Holding at −25° C. effected marked decreases in the total numbers of bacteria present in both salted and unsalted butter but the decreases were much less pronounced in the salted butter than in the corresponding unsalted butter. The destructive action of salt was apparently of greater importance than freezing in reducing the numbers of bacteria in salted butter. No change in flavor was detected in the butter which had been frozen for 90 days. The bacterial counts increased more rapidly and flavor deterioration was more rapid in the unsalted butter held at room temperature (21° C.) after storage at −25° C. than in the fresh butter held 7 days at room temperature. Large numbers of lipolytic and proteolytic bacteria were found in certain lots of unsalted butter after holding at room temperature but no definite correlation could be noted between the growth of these types of bacteria and the development of flavor defects. The bacterial counts did not change significantly in salted butter held 7 days at room temperature subsequent to storage at−25° C. Neither lipolytic nor proteolytie bacteria were detected in the salted butter which had been held 7 days at room temperature subsequent to storage at −25° C. Flavor defects other than tallowiness were not detected in the salted butter when it was held 7 days at room temperature subsequent to storage at−25° C.