The effects of autochthonous probiotic strains of Lactobacillus brevis and Pediococcus pentosaceus on Staphylococcus aureus during production and ripening of white-pickled cheeses

The effects of two autochthonous probiotic strains of Lactobacillus brevis BG18 and ­Pediococcus pentosaceus BH105 were investigated on the growth of Staphylococcus ­aureus. S. aureus counts were monitored separately during production and ripening of white-pickled cheeses by BAM’s 5-tube MPN method. Pasteurized milk used for cheese production with either 1 % Lb. brevis or P. pentosaceus, was artificially contaminated with S. aureus to the mean levels of 6.252 log MPN/mL and 5.952 log MPN/mL, respectively. The study was also carried out with control group cheeses produced without ­adjunct culture. Each positive tube of MPN method was confirmed by PCR amplification of a 400 bp region of the nuc gene. As a result, Lb. brevis BG18 could reduce S. aureus count by 0.4 and 0.7 log units separately during the production (22nd hours) and ripening (92nd day), respectively, when compared to control group cheeses. Whereas P. pento­saceus BH105 could sharply reduce S. aureus counts by 1.8 log units during ripening (92nd day), when compared to control group cheeses. As a result, the present study ­demonstrates the potential use of these autochthonous strains as adjunct cultures in white-pickled cheese production to prevent S. aureus growth which is a great point of importance in respect of food technology as well as food safety.