A determination of raw milk quality and the most suitable microbiological test at the milk collection level in two regions of Kenya

Abstract

A study was conducted in two high dairy potential areas of Kenya to determine the bacteriological and compositional quality of milk produced by small scale farmers and the best microbiological test that could be applied at the milk collection level. A total of 297 milk samples were collected from both study sites. Direct and indirect bacteriological analysis of the milk was done using the total count, coliform count, titratable acidity and resazurin tests. Compositional analysis was done by testing for the fat content, solids not fat (SNF), density, protein and added water using a milk analyzer (Lactoscan). The results obtained from the assessment of the bacteriological and compositional quality were judged against the Kenya Bureau of Standards (KeBS) bench marks. Both regions had most of the samples analysed ( ≥ 77%) within the acceptable bacteriological quality levels. Test for correlation was done between the direct and indirect microbiological tests. Significant positive correlation (P<0.05) was found between the Resazurin test and the Total count and Coliform count test in both study areas. No significant correlation was found between the Titratable acidity and the Total count and Coliform count tests. On compositional analysis, the average pH, fat and the freezing point were within the recommended ranges while the SNF, protein and density were below the recommended ranges. Added water was above the limit set indicating presence of adulteration. Most of the milk collected from the study area was within the established bench marks in Kenya. However, there was need to strengthen milk testing at the collection centre level. The resazurin test was found to be a good indicator test for milk quality that could be applied at the collection level.