Determination of antilisterial effect of some microbial isolates from traditional zlatar cheese during the fermentation of soft white cheese.

The aim of this study was to select autochthonous lactic acid bacteria (LAB) isolates with antilisterial activity from Zlatar cheese and to evaluate the ability of selected LAB to control growth during soft white cheese production. The genotype characterization of isolated LAB (n = 93) was done using PCR method by 16S rRNA sequencing. In this way, the following isolates were detected: ssp. (40 isolates), (30), (12), ssp. (3) (3), (2), (1), (1) and (1). Each isolated LAB was tested for bacteriocin-producing ability. It was determined that two LAB isolates had bactericidal properties: ssp. SRB/ZS/094 and SRB/ZS/090. Semi-purified of enterococcal bacteriocin (enterocin) was isolated using precipitation procedures with ammonium sulphate. Its properties were determined (strength and range of activities). Isolated enterocin and bacteriocin-producing Lactococcus strain showed significant antimicribial activity against , but still the inhibition activity of and was not detected. Based on the obtained laboratory results, in the second phase of the research, the antilisterial effect of bacteriocin isolated from SRB/ZS/090 and cells ssp. SRB/ZS/094 were determined, that are added as additives in the production of soft white cheese through five variants. Cheese supplemented with enterocin (E2) had the lowest aerobic mesophilic bacteria count, indicating that enterocin (E2) play an important role for bio-preservation.