Another set of samples were monitored automatically (recorded every 5 min) during milk acidification for pH using a Cinac system (Alliance Instruments,Mery-Sur-Oise, France), and the corresponding sample were removed to terminate fermentation until a pH of 4.50 ± 0.03 (thepH end point) was reached. After samples were stirred at 500 rpm for 5 min, they were stored at 4 C.