Inhibitory Effect of Fusarium Mycotoxins on Growth of Brewing Yeasts. 2. Deoxynivalenol and Nivalenol*

Abstract

Tlte effect of the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) on growth of Saccharomyces cerevisiae lager and ale strains has been studied. Tlte toxins were added into tlte growth medium in low and high concentrations. Yeast growth was assessed by measurement of dry iveight or relative growth, cell number, viability and conductance change of the growth medium using direct and indirect methods. Tlte inhibitory effect of both DON and NIV on yeast growth was dependent on toxin concentration. Additionally, when tlte 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. Tlte lowest concentrations of mycotoxin causing significant inhibition on growth of brewing yeasts were: 100 \iglml DON for the lager strain and 50 \iglml for the ale strain, and 50 \ig/ml NIV for the ale strain.

The Use and Effects of Lactic Acid Bacteria in Malting and Brewing with Their Relationships to Antifungal Activity, Mycotoxins and Gushing: A Review

“…Flannigan et al 62 observed similar results when ZEN was present at 5-50 µg g -1 , DAS at 5-10 µg g - 1 210 , and DON at 50 µg g -1 176 . Whitehead and Flannigan 210 reported no effect with DON at levels of 20 µg g -1 , while Boeira et al 12 found no effect of NIV at concentrations less than 50 µg g -1 on strains of lager and ale yeasts. In a more recent study, the combined interactions of DON, ZEN and fumonisin B 1 on yeast were observed 12 .…”

“…Whitehead and Flannigan 210 reported no effect with DON at levels of 20 µg g -1 , while Boeira et al 12 found no effect of NIV at concentrations less than 50 µg g -1 on strains of lager and ale yeasts. In a more recent study, the combined interactions of DON, ZEN and fumonisin B 1 on yeast were observed 12 . A synergistic interaction between DON and ZEN was noted, but only at very high concentrations.…”

The Microbiology of Malting and Brewing

“…The toxicogenic effects of DON and related mycotoxins are well established for animals and humans (for a review, see reference 165), leading to the adoption of strict quality standards for DON in malt. In addition to potentially threatening human health, high concentrations of these mycotoxins have been shown to inhibit yeast growth during beer fermentation (166,167).…”

Mycotoxin Decontamination Aspects in Food, Feed and Renewables Using Fermentation Processes

“…It was found that Fusarium-contaminated wheat with a high concentration of DON (3.95 mg kg −1 ) negatively affected the fermentation by S. cerevisiae process and reduced the ethanol concentration by 13.5% in the fermented wort ( Figure 5). The explanation for the decrease in the ratio of fermentation by S. cerevisiae might be the inhibitory effect of high concentrations of Fusarium mycotoxins on yeast growth [147]. Whitehead and Flannigan [148] suggested that trichothecenes inhibit mitochondrial function, causing slower oxygen utilisation by the yeast resulting in a slower growth rate.…”