[Preparation of the mycotoxin ochratoxin A for research and diagnostic purposes].

The following fungal strains were tested for the production of the mycotoxin ochratoxin A: Aspergillus melleus (CCM F 802), Aspergillus ochraceus (CCM 8002) and Aspergillus ochraceus (CCM F 803). The strain Aspergillus melleus (CCM F 802) proved to be very suitable for the laboratory preparation of ochratoxin A. The mould was multiplied on a natural substrate for 14 days at the temperature of 28 degrees C and at 100% relative humidity. Ochratoxin A was extracted into organic solvents (chloroform + acetic acid), purified with aqueous alkaline solutions and by preparative thin-layer chromatography. The isolated mycotoxin was identified by physico-chemical methods. The amount of pure ochratoxin A isolated from 600 g of substrate was 305 mg.