COMPETITIVE-INHIBITION OF ASPERGILLUS-FLAVUS BY VOLATILE METABOLITES OF RHIZOPUS-ARRHIZUS

In this work a feasible application of the antifungal activity of the volatile metabolites produced by a strain of Rhizopus arrhizus has been investigated. The effect of such metabolic vapours, of their individual components, such as ethanol, isobutyl alcohol and 3-methyl butanol, or of their mixtures on Aspergillus flavus growth, both in semisynthetic media and miniaturized bread loaves, has been studied. The antifungal activity attributable to these primary metabolites, when present in the vapour phase at levels ranging between 3 and 6% (v/v of head space), was synergistically enhanced by a decrease of the aw in the food model systems. The physical state of the alcohols, i.e. their partition between solid and gaseous phases, also dependent on the aw of the system, seems to be one of the determinants for their antifungal activity. © 1993 Academic Press Limited.