Inhibitory effect of Fusarium mycotoxins on growth of brewing yeasts.: 2.: Deoxynivalenol and nivalenol

The effect of the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) on growth of Saccharomyces cerevisiae lager and ale strains has been studied. The toxins were added into the growth medium in low and high concentrations. Yeast growth was assessed by measurement of dry weight or relative growth, cell number, viability and conductance change of the growth medium using direct and indirect methods. The inhibitory effect of both DON and NIV on yeast growth was dependent on toxin concentration. Additionally, when the extent of inhibition of yeast growth caused by high concentrations of both toxins was observed, it was subject to yeast strain, length of incubation and method used to assess yeast growth. The lowest concentrations of mycotoxin causing significant inhibition on growth of brewing yeasts were: 100 mu g/ml DON for the lager strain and 50 mu g/ml for the ale strain, and 50 mu g/ml NIV for the ale strain.