For the initial evaluation of the effect of raw milk acidity on the yield of cheese making, full fat (7.4%) buffalo milk was stored at environment temperature (20 ° C) for letting the acidity to increase naturally. The evaluated acidity points of the raw milk were 16° , 18° , 20° and 22° Dornic. Upon reaching to different acidity levels, four batches of the milk (8 kg every batch, for one acidity level) were weighed and were used for subsequent processing. To minimize the probable differences of raw materials and the elimination of possible errors, all of the samples were obtained from the same livestock and were divided into four batches. Each 8 kg batch was pasteurized at 63 ° C for 30 min and af terwards,
was divided into four two Kg samples (as replications) that were cooled to 34 ° C. One percent VisBy vAc-Seri 50-G2 starter culture and 0.015% CaCl2 were added to each sample and after about 20 min, the samples were supplemented by a fungal rennet enzyme (Rennilaseiiec- Novo NorDisk- A/s, Bagsvaerd, Denmark) as recommended by the producer (1 g/25 l). After renneting, the milk was mixed well (2–3 min) and after the mixing process, it was stored unmixed for coagulation. The next step after complete coagulation, which took about one hour, was the cutting step through which the curd was cut into 2 cm3 pieces. The wheying off stage was subsequently performed in about 15 min (Whey samples were chosen for evaluation at this stage). The cut curd pieces were pressed while stored in burlaps for approximately 2.5–3 h
and the weight of the pressing materials (steady press under gravity) was considered to be almost equal to that of the curd. After pressing the curd, it was cut into cubes and then the cubes were stored in pasteurized brine (22% NaCl) at 16 °C for about 10 h. Finally, the samples were evaluated for pH, moisture content and fat content. The yield of cheese making was also calculated at this stage. As it was stated before, 3–4 batches of cheese were produced for every single test. The experimental design for this step was a completely randomized design for the analysis of variance (ANOVA). Regression analysis was also performed, if necessary, to reveal any relationship between the evaluated factors and measured parameters.