2.4. Microbiological determinations
Representative cheese samples (5 g), including both cheese surface and core, were homogenized with 45 mL of a sterile 2% (w/v) sodium citrate solution at 45 C in a Stomacher 400 (A. J. SewardLtd, London, UK). Decimal dilutions of cheese homogenates were prepared in sterile 0.1% (w/v) peptone solution. Lactococci counts from commercial starter were determined on duplicate plates of Tryptic Glucose Yeast agar (Biolife) with 0.1% added skim milk (Biolife), after aerobic incubation for 24 h at 30 C. Clostridial spore counts were determined on RCM agar as described in Section 2.2. Microbiological analyses were carried out at 1, 7,15, 30 and 60 days.