Direct microscopic leucocyte counts (DMLC) and morphological studies indicated that leucocytes disintegrate and lysis progresses rapidly from day 1 to day 2 in milk samples during storage. The average DMLC/ml decreased 34% during the first two days of storage. The reactivity of the samples to the California Mastitis Test decreased with sample age. These combined observations suggest that deoxyribonuclease (DNA), once free of the intact leucocyte, becomes less reactive or non-reactive to the test reagents. Milk samples which produced more than 20% O2 gave highly reproducible results when tested by the catalase method. Those which produced less than 20% gave erratic results.
1Contribution from the Missouri Agricultural Experiment Station. Journal Series Number 4086.
2Present Address: University of Pittsburgh, Graduate School of Public Health.