Microbial factors affecting the quality of raw cow's milk
2004
Konosonoka, I.H.,Latvia Univ. of Agriculture, Sigulda (Latvia). Research Centre Sigra | Jemeljanovs, A.,Latvia Univ. of Agriculture, Sigulda (Latvia). Research Centre Sigra
In total, 713 bulk milk samples and 92 quarter milk samples were investigated using conventional bacteriological methods at the Department of Veterinary Medicine of the Research Centre Sigra of the Latvia University of Agriculture. Bulk milk samples did not exceed permissible level of microbial contamination in 70.4% of all cases, but in 29.6% of cases it was exceeded. The average bacterial counts in bulk milk samples were 2 241 400 CFU mlE-1, which points to violation of the veterinary sanitary regulations in the milking process. Staphylococcus spp. were isolated from 96.3% of quarter milk samples. Using the BBL Crystal Identification System for gram-positive microorganisms, some Staphylococcus species were identified - coagulase positive Staphylococcus aureus and coagulase negative Staphylococcus haemolyticus, Staphylococcus simulans, Staphylococcus hyicus, Staphylococcus xylosus. The numbers of staphylococci in the quarter milk samples were different. In 46.0% of cases they exceeded 2 000 cfu mlE-1, which suggests subclinical udder inflammations. The somatic cell count in quarter milk samples with the number of staphylococci over 2 000 cfu mlE-1 was 3.1 times higher compared to samples with the number of staphylococci below 2 000 cfu mlE-1.
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