IMMUNOCHEMICAL DETECTION OF OCHRATOXIN-A IN BLACK ASPERGILLUS STRAINS

One hundred and fifty-seven strains belonging to Aspergillus section N igri were tested for ochratoxin A production using three different met hods: a relatively new immunochemical method based on an enzyme-linked immunosorbent assay (ELISA), thin-layer chromatography (TLC) and high -performance liquid chromatography (HPLC). The monoclonal antibody-bas ed ELISA technique was successfully used to screen for low levels of o chratoxin A in the black Aspergilli without concentrating the culture filtrates. The results were confirmed by TLC and HPLC analysis and che mical derivatization. These latter methods required concentrated filtr ates. Ochratoxin A was detected in the culture filtrates of five of th e 12 A. carbonarius strains, none of the 45 A. japonicus strains and t hree of the 100 isolates in the A. niger aggregate (A. foetidus, A. aw amori and A. niger).