Comparative study on the quality characteristics of yoghurt produced by caw milks with different somatic cells count

Abstract

The present study aimed to provide the necessary information for the effect of somatic cells count (SCC) of raw cow milk on the fermentation process and quality characteristics of yoghurt.

Test yoghurt samples were produced from three different batches of cow milk with low (< 400 000 cells.cm(-3)), medium (between 500 000 and 600 000 cells.cm(-3)) and high (1 000 000 cells.cm(-3)) SCC, respectively. The main physicochemical parameters as pH, total solids, milk fat, protein, lactose, lactic acid content and microbiological parameters as somatic cells count (SCC) and total viable count (TVC) of raw milk and yoghurt samples were studied. It was found that, the SCC of the raw milk did not have a significant effect on the composition and pH values of the yoghurt. A similar rate of acidification during fermentation of the milks having different SCC, as well as during the cold storage of yoghurt samples was established. The variations in the SCC of the raw milk within the range up to 500 000 cells.cm(-3) had no significant effect on the organoleptic properties of the yoghurt. The increase in the SCC values up to 1 000 000 cells.cm(-3) in the raw cow's milk affected negatively the organoleptic characteristics of the yoghurt made from it.