Somatic cell count on proteolysis in mozzarella cheese

Abstract

The aim of this trial was to evaluate the effect of somatic cells count on the microbiota and proteolysis of Mozzarella cheese during the storage period. Cows presenting different levels of SCC were selected: 200,000 cells/mL; >200,000 to 400,000 cells/mL; >400,000 cells/mL to 750,000 cells/mL and >750,000 cells/mL, which were not treated with antimicrobial prior or on the milk sampling day. The cheeses produced were evaluated after 1, 15 and 30 days of storage for coliforms count at 35ºC, coliforms count at 45ºC, psychrotrophic and lactic acid bacteria. Meanwhile, extent and depth of proteolysis indexes were determined. The complete trial was repeated four times and experimental design used was randomized blocks. ANOVA was used for repeated measurements and the p-value was adjusted for multiple comparisons by Tukey's test. High somatic cell count milk showed lower concentration of protein and higher of non-protein nitrogen. There was a decrease of lactic acid bacteria in cheese made from milk containing high somatic cells count (>750,000cells/mL). Nevertheless, during the storage period, a significant increase in the extent and depth of proteolysis occurred in cheeses produced from milk with SCC higher than 400,000 cells/mL. Therefore, in order to produce a high quality Mozzarella cheese, it is necessary to control the raw material, so that SCC should be lower than 400,000 cells/mL.