T.SATHIAN, C.ANU JOSEPH, PEREKATTU2019-06-262019-06-262016KVASU REFERENCE CITATIONhttp://krishikosh.egranth.ac.in/handle/1/5810110073Objectives of the research work were to find out the impact of somatic cell count (SCC) on the physicochemical properties of milk and on the quality of fermented dairy products, curd and yoghurt. The correlation between the somatic cell count and total DNA content isolated from the milk was also explored. In this study one hundred pooled cow milk samples were collected from farms and milk co-operative societies in Thrissur district. The samples were categorised into three groups based on SCC into low, intermediate and high. All the pooled cow milk samples were subjected to Methylene Blue Reduction Test, isolation and quantification of DNA. Somatic cell count, pH, titratable acidity, chloride content, and electrical conductivity of the samples were estimated. On analysis, it was found that pH showed a negative correlation and titratable acidity showed a positive correlation with high SCC category milk. Chloride content as well as electrical conductivity of milk showed a significant positive correlation (P< 0.01) with SCC in milk. An elevated somatic cell count in milk was associated with poor microbial quality of raw milk revealed by Methylene Blue Reduction Test. Pearson’s analysis showed a significant positive correlation (P<0.01) between the DNA yields extracted from the pooled cow milk and the milk Somatic cell count. Yoghurt and curd prepared from milk with varying SCC (low, intermediate and high) were evaluated for the starter activity, free fatty acid content, viscosity and sensory evaluation. The free fatty acid content of the high SCC yoghurt and curd were significantly higher than the low SCC yoghurt and curd (P<0.05). Starter activity of high SCC yoghurt was significantly lower (P<0.05) than the low and intermediate SCC yoghurt, while the starter activity of curd showed no difference among the three groups (P>0.05). Sensory evaluation of the products revealed that there was a negative correlation (P<0.05) between the sensory scores and SCC of milk. It was concluded that the milk with SCC greater than 5x105cells/ml had negative impact on the quality of milk and milk products. Estimation of DNA content of milk will provide a good technique for enumeration of SCC in milk.ennullThesis