Caratterizzazione chimica, enzimatica e microbiologica del latte e della mozzarella di bufala prodotti in provincia di Foggia

SUMMARY – Chemical, enzymatic and microbiological features of buffalo milk and mozzarella cheese produced in the province of Foggia. The experiment was conducted in three buffalo dairy farms located in the province of Foggia (Apulia, Italy). Bulk milk was analyzed for chemical, hygienic and enzymatic parameters and the impact of milk features on mozzarella cheese quality was investigated. Three sampling cycles were performed in each farm at weekly intervals; bulk milk collected from each farm was processed for mozzarella cheese production according to an industrial protocol. Milk somatic cell count was always lower than 3 log10 SCC/mL and bacterial cell load was lower than 5 log10 cfu/mL and 3 log10 cfu/mL for total bacterial count and total coliforms, respectively. These results evidenced a good hygienic quality of buffalo milk due to a good dairy farming practices. Endogenous proteolytic enzymes as plasmin-plasminogen system, cathepsin D and elastase displayed activities lower than those detected in cow, sheep and goat milk due to the lower somatic cell count in buffalo milk. Moreover, these enzymes were affected by the processing technology of mozzarella cheese; in particular, the acidification step could be responsible for the higher activity of cathepsin D whereas the stretching phase may be involved in the conversion of plasminogen to plasmin. Finally, principal component analysis was performed on a matrix of 16 fatty acids to discriminate acidic profile of buffalo milk and mozzarella cheese. Fatty acid profile reflected the one recorded in the corresponding milk due to the absence of the lipolytic process occurring during cheese ageing.