PRODUCTION OF PATULIN AND CYTOCHALASIN-E BY ASPERGILLUS-CLAVATUS DURING MALTING OF BARLEY AND WHEAT

Production of patulin and cytochalasin E by four strains of Aspergillu s clavatus during small-scale laboratory malting of barley at 16 and 2 5 degrees C was investigated. Fungal biomass, measured as ergosterol, appeared to be greater at 25 than at 16 degrees C, but marked differen ces were observed between the degree of colonization by the different strains. Patulin was detected in extracts by HPLC. Net production was greater at 16 degrees C, but amounts were strain dependent. Except for one strain, cytochalasin E was detected only in barley malted at 25 d egrees C. In experiments with wheat inoculated with two A. clavatus st rains, ergosterol levels in the green malts were generally greater tha n in corresponding barley malts. Patulin was again detected in all sam ples, with the equivalent of 22.4 mg/kg being detected in one sample a t 16 degrees C, but cytochalasin E was only found at 25 degrees C, the highest level detected being 13.8 mg/kg. In samples of barley spiked with toxin and kilned at 80 degrees C for 24 h, only about one-fifth o f the amount of toxin recovered from corresponding unkilned controls w as detected. It is indicated that differences in both contaminant stra ins and temperature in different maltings may account for disparities between symptoms reported for individual outbreaks of mycotoxicosis as sociated with malting by-products. (C) 1997 Elsevier Science B.V.