Antifungal Effect of Lactobacilli on Fusarium and Aspergillus Molds

Abstrakt

The aim of this project is selection of Lactobacilli cultures for production of fermented products which include both milk and cereal components. Antifungal activity of ten Lactobacilli strains from two culture collections against Fusarium spp. and Aspergillus spp. was tested by the agar diffusion method. In the following step the inhibitory effect of Lactobacilli on growth and mycotoxin production of Asp. flavus DMF 0802 and Asp. parasiticus DMF 0805 was determined by common cultivation in liquid media using the method of mycelium weight and aflatoxin B1 detection by HPLC. The highest activity of Lactobacilli cells against molds was detected for strains Lbc. curvatus 2775 and Lbc. curvatus 2768. The supernatants of strains Lbc. paracasei 05 and Lbc. curvatus 2768 were the most active. The most significant weight change of the mycelia of Asp. flavus DMF 0802 compared with control was observed in the initial growth period of the mould on day 5 (58−-83 %). An important change was detected on day 14 in cultivation of Asp. parasiticus DMF 0805, when the mycelium weight increased rapidly in the presence of almost all Lactobacilli strains compared with control (86−-137 %). The production of aflatoxin B1 by Asp. flavus DMF 0802 strain was inhibited. The production of aflatoxin B1 by Asp. parasiticus DMF 0805 strain was detected on day 5 of joint cultivation with Lactobacilli, and the maximum concentration was detected on day 8 (20-−200 ng ml⁻¹). In the next days of cultivation, the concentration of aflatoxin B1 decreased.