Relationship of mould count, ergosterol and ochratoxin A production

The relationship between viable mould count, ergosterol content and ochrato xin A (OA) formation was studied at different inoculum concentrations of As pergillus ochraceus NRRL 3174 and Penicillium verrucosum NRRL 3260 own on s terile long-grain enriched white rice as the substrate. Ergosterol was dete rmined by extraction, saponification and quantification using hi.-h perform ance thin layer chromatography (HPTLC) with UV detection. Ergosterol and oc hratoxin A were detected after 3 days of incubation and reached their maxim um at 7-10 days of incubation. After that, a decline in the concentrations in both ergosterol and ochratoxin was observed. Ergosterol measurement by H PTLC appeared to be a useful method to detect fungal activity, which corres ponded to ochratoxin production. Thus, the ergosterol assay may have a use as an early indicator of potential mycotoxin production. (C) 2001 Elsevier Science B.V. All rights reserved.