Quality assessment of raw camel milk using dye reduction tests

The composition of camel milk is different from cows’ milk and this has a bearing on the quality assessment parameters. To date the quality control tests used on camel milk are those established for cow milk despite the compositional differences especially the high antimicrobial substances in camel milk. The objective of this study was to establish whether the reported high indigenous antimicrobial substances in camel milk have any effect on the reductase activity of dye reduction tests in assessing raw camel milk quality. The 10-minutes resazurin and total viable bacterial count tests were carried out on pooled fresh camel milk and pooled fresh cow milk. The same samples were inoculated with 3 % cow milk with zero (0) resazurin disc reading and further subjected to 10-minutes resazurin, titratable acidity and total viable bacterial count tests. The study established that the reported high antimicrobial substances in camel milk do not inhibit its bacterial spoilage. This was shown by the high bacterial load and high developed acidity in the inoculated camel and cow milk samples. However, the reductase activity for the 10-minutes resazurin test was much lower in camel milk compared to cow milk at ( α ≤ ≤ ≤ ≤ 0.05) which is an indication that the former has more inherent hydrogen acceptors responsible for the observed delayed reductase activity. The results of this study indicated that dye reduction tests are not appropriate for assessing the quality of raw camel milk.