OCHRATOXIGENICITY OF ASPERGILLUS-OCHRACEUS GROUP AND PENICILLIUM-VERRUCOSUM VAR CYCLOPIUM STRAINS ON VARIOUS MEDIA

Production of ochratoxin A (OA) by strains of Aspergillus ochraceus gr oup (A. ochraceus - 21, A. sclerotiorum - 1, A. sulphureus - 1) and Pe nicillium verrucosum var. cyclopium strains - 11, on various media was investigated. Thirteen percent of A. ochraceus strains and 18% of P. verrucosum var. cyclopium formed OA growing on sterile crushed wheat f or 14 days at 25 to 27-degrees-C (preliminary experiments). Toxin conc entrations were 5.0 to 7.0 mug/kg. Five strains OA-positive on crushed wheat and four OA-negative strains were cultivated on various liquid nutritional media (YES, RM, OAT, CG and AFP). All the strains tested, including OA-negative ones, produced OA on certain liquid media. Conce ntrations of OA were low again (trace to 16.0 mug/l). ne largest numbe r of mould strains examined produced OA on YES (553%) and RM media (44 .0%), but the highest concentration (16.0 mug/l) was formed on YES and CG media.