Influence of pig rennet on proteolysis, organic acids content and microbiota of Pecorino di Farindola, a traditional Italian ewe's raw milk cheese

The use of pig rennet is very ancient and in Italy is only applied in the manufacture of Pecorino di Farindola cheese. In order to evaluate the key role of this rennet in the establishment of peculiar features of Pecorino di Farindola, cheeses made from raw ewes' milk using calf (A) and kid (B) rennets were compared to those produced with pig (C) rennet. The use of pig rennet for Pecorino di Farindola cheese making confers physico-chemical and proteolytic characteristics that differentiate it from cheeses produced with other coagulants. However, no microbiological differences were observed. Chesses made with pig and kid rennets were characterised by higher proteolysis after 7 days of ripening. The content of isovaleric and propionic acids at the end of ripening was correlated with the presence of propionibacteria.