Ochratoxinogenicity of Aspergillus ochraceus strains from nephropathic and non-nephropathic areas in Yugoslavia

Abstract

Mycological analyses of 855 samples of stored grains and dried meat collected in period 1980-1987 from individual households in the nephropathic and wider non-nephropathic area in SR Croatia in Yugoslavia showed 10% of samples to be contaminated with Aspergillus ochraceus. Ability to produce ochratoxin A (OA) was tested in 70 samples (27 from nephropathic areas and 43 from non-nephropathic areas). The detection was carried out under UV-light (365 nm) (light blue fluorescence) and 6 OA-producers were found. A biosynthetic procedure on liquid nutritional substrate with saccharose and yeast extract as well as a method using wet crushed wheat revealed that 37% of the samples from a nephropathic area, and 35% of the samples from a non-nephropathic area produce OA. In the nephropathic area 1/10 strains was a strong producer of OA (concentration crushed wheat 135 mg/kg, and 240 mg/l on YES liquid substrate), 1/10 strains was a moderate producer (concentration 16.6 mg/l and 0.07-7.0 mg/l and 0.1-10.4 mg/kg). Among the strains isolated from a wider non-nephropathic area no strong producers of OA were found, but 2/15 strains were moderate producers of OA (concentration of OA 20.4-27.0 mg/l and 15.0-33.7 mg/kg). The other strains, 8/10 on the crushed wheat and 13/15 on the liquid substrate, were weak producers of OA with concentrations of OA between 0.2-9.0 mg/l and 0.2-10.0 mg/kg with the two methods respectively.