CLASSIFICATION OF BOVINE-MILK SAMPLES BY USING A NEW N-ACETYL-BETA-D-GLUCOSAMINIDASE ACTIVITY MEASUREMENT

A new, simple and rapid spectrophotometric method for N-acetyl-beta-D- glucosaminidase (NAGase) activity measurement using Clarifying Reagent (R) has been applied to the differentiation of some individual milks t owards a possible mastitis. Enzymatic activity measured by this method on 52 individual raw milk samples was well correlated (r=0,80) to the somatic cell count (SCC). The NAGase activity measured by the usually spectrofluorometric method was also well correlated to the SCC (r=0,7 6). The 52 individual raw milk samples have been distributed among 3 c lasses according to their SCC. Class I with SCC<200,000 collected samp les of good hygienic quality. Class II with SCC ranged from 200,000 to 400,000 identified doubtful samples and class III with SCC>400,000 co ntained suspicious mastitic or submastitic milk samples. The 2 used en zymatic methods permit the same classification of these milk samples w ith the 3 significantly different classes. NAGase activities of classe s I and II partially overlay, but their mean values were significantly different. Experiments on 5 samples have demonstrated that the spectr ophotometric method is also suitable for differentiation of bulk milk. This study shows, that it is possible to classify milk samples accord ing to their degree of infection by using only NAGase activity.