Quantity of selected probiotic cultures in semi-hard cheese with low-cooking curd during the maturation process.

The work studies the survival of added selected probiotic bacteria Lactobacillus acidophilus (S1), Lactobacillus casei (S2), and Lactobacillus plantarum96 (S3) in semi-hard cheese with low-cooking curd during the maturation process. Cheeses were made according to the standard procedure (Polyfood SI 050 device). Probiotic lactobacilli strains Lactobacillus acidophilus (S1), Lactobacillus casei (S2), and Lactobacillus plantarum96 (S3) used in this study were added into the milk before the renneting process. The manufactured cheeses were matured for 6 months at the temperature of 10 °C. Cheese samples were taken for pH and titratable acidity measurements, lactobacilli enumeration, and chemical analysis at 30, 60, 90, 120, 150 and 180 days of maturation. At the end of the experiment (180 days) the cheese samples were analyzed also for the amount of lactic acid and protein contents. Initial numbers of lactobacilli inoculated into the milk (10(8) CFU mL(-1)) decreased during the first 2 weeks of maturation and reached from 2.15 10(7) CFU g(-1) in S1 cheese to 4.32 10(7) CFU g(-1) in S3 cheese. The number of Lactobacillus acidophilus strain bacteria at the beginning of the maturation period was 2.47.10(7) CFU g(-1) and declined until day 120 of maturation to the number of 0.45 10(6) CFU g(-1). In the last month of the experiment day 180 the viable cell numbers started to rise up to the final number of 0.41 10(7) CFU g(-1). The numbers of Lactobacillus plantarum96 varied around 10(8) CFU g(-1) during the whole period of the experiment. According to our results it was detected that in all experimental cheeses, the used probiotic lactobacilli reached the values above 10(6) CFU g(-1). Thus the legislated and therapeutic minimum limits set for the products containing probiotic bacteria for human diet were fulfilled.