Effects of Propionibacterium on the growth and mycotoxin production by some species of Fusarium and Alternaria.

The aim of this research was to study the antifungal properties of propionibacteria. Three fractions from cultures of Propionibacterium freudenreichii ssp. shermanii 41 and ssp. freudenreichii 111 (i.e. culture containing viable bacteria, cell-free supernatant and bacteriocin preparation) were tested for their ability to inhibit the growth and mycotoxin production of Alternaria alternata, Fusarium culmorum, Fusarium graminearum and Fusarium verticillioides. The growth of the fungi was monitored during cultivation using a plating method. The concentration of toxins produced was measured by HPLC on the 14th day of culture. Altenuene and tenuazonic acid were determined in cultures of A. alternata whilst concentration of nivalenol, deoxynivalenol, fumonisin B1 and zearalenone was measured in Fusarium cultures. The strongest inhibition of growth and toxin production was observed in the presence of cultures containing viable cells and supernatants obtained from propionibacteria cultures. The bacteriocin extracts generally had a weak fungistatic effect on the growth of A. alternata, F. culmorum and F. graminearum. Despite the fact that growth was slower in the presence of bacteriocin extracts than in control trials, none of the preparations prepared from the propionibacteria significantly reduced the level of mycotoxin production. The ability of P. freudenreichii ssp. freudenreichii 111 to remove zearalenone from liquid medium was also evaluated. It was shown that both viable and non-viable cells caused a decrease in zearalenone concentration in the medium.