The in Vitro Antifungal Activity of Lactobacillus Spp. Against Aspergillus Ochraceus Growth and Its Ochratoxin a Production

Abstract

This study was aimed to monitor the inhibitory effect of selected species of the genus Lactobacillus on growth and ochratoxin A production of the microscopic filamentous fungus Aspergillus ochraceus (SLO-B-245). Nine species of the genus Lactobacillus were used in this study, namely L. bifermentatus. L. perolens, L. reuteri, L. paracasei, L. paraplantarum, L. plantarum, L. salivarius, L. fructivorans and L. pentosus. All strains were isolated from dairy products and their identification was performed by MALDI TOF MS (Bruker Daltonics, Germany, Maldi Biotyper). The antifungal activity was carried out using the overlay technique. Solid culture media inoculated with bacterial and fungal inocula were cultivated under aerobic conditions at 37 ºC for 8 days. Diameters (Ø mm) of the grown fungal colonies were measured every two days. To determine the inhibition of ochratoxin A production, the thin-layer chromatography method (TLC) was used. L. plantarum and L. paraplantarum were able to inhibit the growth of A. ochraceus (SLO-B-245) completely (100% inhibition), while L. fructivorans appeared to be the least effective (10.73%). Interestingly, the latter one was able to completely inhibit or partially suppress ochratoxin A production. We hope that our results can contribute to the search for harmless substances for the biological control of fungi in food. Lactobacilli and similar organisms could be very promising alternatives for food preservation.