Effects of three Fusarium species on the quality of barley and malt

n this study, field-grown barley was artificially infected during the heading stage with three Fusarium species, F. culmorum, F. graminearum, and F. poae. The objective was to investigate possible differences among Fusarium species in terms of how severely they affect the quality of barley under Finnish field conditions. Moreover, we studied the effects of heavy infection on corresponding malt quality. Field trials were carried out with two different barley cultivars at two experimental farms. Spike samples collected during the growing period were analyzed for Fusarium infection and moisture content. Total precipitation and temperature data were collected daily. In addition, the harvested barley samples were analyzed for overall microbial flora and for mycotoxins. The infection rate and the amount of mycotoxins produced in the barley samples differed among species. F. graminearum was found to have the most negative effects on barley quality in terms of the studied parameters. Samples were malted in laboratory scale. All three Fusarium species increased the gushing potential of malt. Heavy fungal infection increased the enzyme activities in malt resulting in darker wort color and increased soluble nitrogen and free amino nitrogen content. However, high Fusarium contamination reduced lautering performance.