Mycotoxins of Aspergillus clavatus: Toxicity of cytochalasin E, patulin, and extracts of contaminated barley malt

Brine shrimp and conductimetric Saccharomyces cerevisiae bioassays were used to investigate the toxicity of green barley malt prepared at 16 and 25°C from grain inoculated with a strain of Aspergillus clavatus known to produce the mycotoxins cytochalasin E and patulin during malting. Pure cytochalasin E was considerably more toxic to brine shrimp larvae than patulin (LC₅₀ < 0.5 versus >30 µg ml^-1). In contrast, patulin significantly inhibited growth-related change in conductance of S. cerevisiae cultures at a concentration of 10 µg ml^-1, but cytochalasin E had no effect at 80 µg ml^-1. Extracts of both 16 and 25°C malts contaminated with A. clavatus were toxic to brine shrimp larvae, but had only limited inhibitory effects on the growth of S. cerevisiae. Since concentrations of cytochalasin E in contaminated malts produced at 16°C are below or close to the limits of detection, the presence of other fungal metabolites toxic to brine shrimps in such malts is indicated.