Standardisation of traditional rennet produced from sheep abomasum

Abstract

Traditional rennet (TR) from small ruminants is required to produce many cheeses, but can be a source of technological and safety problems due to low milk-clotting activity (MCA) and microbiological quality. TR samples were obtained from producers of Erzincan tulum cheese in the Gölyurt plateaus (Turkey). Total aerobic mesophilic bacteria, yeast and moulds, total coliforms, Escherichia coli, Staphylococcus aureus, and anaerobic spore-forming bacteria counts in the TRs were in the ranges of <1 to 8.07 log cfu mL−1, <2 to 7.33 log cfu mL−1, <1 to 4.32 log cfu mL−1, <1 to 3.19 log cfu mL−1, <1 to 3.46 log cfu mL−1, and <1 log cfu mL−1, respectively. In standardising the TRs, microfiltration decreased the number of microorganisms (<1–2 log cfu mL−1); evaporation increased the MCA by 5 times and reached 1:806–1:5336 MCU mL−1. As a result, increased microbiological safety and MCA of standardised rennet and improved sensory properties of cheese were obtained by a practical and reproducible process.