[A study on the pectinase-producing abilities of Aspergillus flavus in grain of Zhejiang Province].

Eighty strains of Aspergillus flavus were isolated from 110 specimens of rice, wheat flour and malt, and their pectinase-producing abilities were studied in toxigenic and non-toxigenic strains. Levels of pectinase-production by A. flavus were determined with measuring the diameter of the colourless and transparent zone formed around the colonies stained with ruthenium red. Toxigenic strains with high levels of pectinase-production (with a diameter of transparent zone more than 5 mm) accounted for 82.6% and non-toxigenic strains for 42.1% of the total, respectively, and their difference reached a significant level. The level of pectinase-production in toxigenic strains was higher than that in non-toxigenic ones.