Analysis of microbiological variation in PDO Vastedda della valle del Belìce cheese during the storage period

Abstract

The PDO “Vastedda della valle del Belìce” is a Sicilian pasta filata sheep cheese, made from raw milk without starter addition. It is a small round cheese without rind, weighing about 500-700 g. It is cheese is marketed also out of Sicily to allow its marketing and to prolong its shelf-life. The aim of this work was to evaluate the variation of microbiological parameters during the shelf-life period. Then 162 Vastedda cheeses from 18 cheese-making processes in 7 farms have been analysed at different times of storage at 4°C (0, 15, 30, 45, 60, 75, 90, 105, 120 days). Coliforms and E. coli were detected into 7/18 cheese-making processes and their count decreased during the storage period. Enterococci were more resistant to high temperature achieved during the stretching and their were rather stable during storage period (105 cfu/g). The concentration of total Bacterial Count and Mesophilic Lactococci were around 107 cfu/g, while the concentration of Thermophilic Lactococci was higher (108 cfu/g) probably due to the stretching at 90°C. In conclusion, this study shows the good sanitary conditions of cheeses. Overall, the lactic flora was kept alive and vital at high concentration (> 107 cfu/g) until 120 days of storage.