Fungistatic and antagonistic properties of the complex of probiotic cultures S. thermophilus, L. bulgaricum and L. rhamnosus

Abstract

Goal. To study the fungistatic and antagonistic properties of the complex of probiotic cultures of Streptococcus thermophilus, Lactobacillus bulgaricum and Lactobacillus rhamnosus concerning the epizootic topical saprophyte Aspergillus flavus. Methods. Accepted and developed in the laboratory of toxicological monitoring mycological and bacteriological methods of cultivation and identification. Results. When studying the fungistatic properties of probiotic cultures of S. thermophilus, L. bulgaricum and L. rhamnosus against Aspergillus flavus, it was found that the complex of lactic acid bacteria in dilutions of 2·109, 2·108, 2·107, 2·106 and 2·105 bacterial cells under exposure time for 60, 90 and 120 min at a temperature of 20±0.5 and 37±0.5°C did not have effect on the growth retardation of the museum strain and field isolate of A. flavus. Continuous growth was observed of test cultures of micromycetes, compared with its complete absence in negative control with nystatin. When studying the antagonistic properties of probiotic cultures of S. thermophilus, L. bulgaricum, L. rhamnosus in dilutions of 2·109, 2·108, 2·107, 2·106 and 2·105 bacterial cells for 18-20 h of incubation at a temperature of 37,0±0.5°C growth retardation zones of the museum strain and field isolate of A. flavus were not detected, whereas in the negative control, the diameter of the growth retardation zone was 24 and 26 mm, respectively. That is, probiotic cultures of S. thermophilus, L. bulgaricum, L. rhamnosus did not show antagonistic properties against the museum strain and field isolate of A. flavus. Conclusions. The complex of probiotic cultures of S. thermophilus, L. bulgaricum, L. rhamnosus in concentrations of 2·109, 2·108, 2·107, 2·106 and 2·105 in experiments in vitro did not show fungistatic and antagonistic properties. The continuous growth of A. flavus was found in all studied dilutions, compared with its complete absence in negative controls with nystatin.