Effect of somatic cell count in goat milk on yield, sensory quality, and fatty acid profile of semisoft cheese

This study investigated the effect of somatic cell count (SCC) in goat milk on yield, free fatty acid (FFA) profile, and sensory quality of semi-soft cheese. Sixty Alpine goats without evidence of clinical mastitis were assigned to three groups with milk SCC level of <500,000 (Low), 500,000-1,000,000 (Medium), and 1,000,000-1,500,000 (High) cells/mL. Thirty kilograms of goat milk with mean SCC levels of 410,000 (Low), 770,000 (Medium), and 1,250,000 cells/mL (High) was obtained for the manufacture of semi-soft cheese for two consecutive weeks in three lactation stages. The composition of milk was analyzed and cheese yield was recorded on day 1. Cheese samples on day 1, 60, and 120 were analyzed for scores of total sensory, flavor, body/texture by a panel of three expert judges, and FFA. Results indicated that the milk composition did not change when milk SCC varied from 214,000 to 1,450,000 cells/mL. Milk with higher SCC had a lower standard plate count while Coliform count and psychrotrophic bacteria count were not affected. However, milk components (fat, protein, lactose, casein and total solid) among three groups were similar. As a result, no significant differences in the yield of semi-soft goat cheeses were detected. However, scores of total sensory and body/texture for cheeses made from the high SCC milk were lower than those from the low and medium SCC milk. The difference in milk SCC levels also resulted in diverse changes in cheese texture (hardness, springiness, etc.) and FFA profiles. Individual and total FFA increased significantly during the ripening, regardless the SCC levels. It is concluded that SCC in goat milk did not affect the yield of semi-soft cheese, but resulted in inferior sensory quality of aged cheeses.