Ochratoxin A production in aniseed-based media by selected fungal strains and in anise fruits (Pimpinella anisum L.)

Abstract

The growth conditions and ochratoxin A (OTA) production of Aspergillus strains were studied in aniseed (Pimpinella anisum L.)-based media. The results showed that methanol/NaHCO3 (50:50, v/v) mixture for extraction and competitive direct ELISA analytical method are capable of detecting low OTA concentrations in this raw material, which were confirmed by HPLC with fluorescence detection (R (2) = 0.994). In aniseed meal extract agar artificially contaminated with selected fungi, the higher OTA values obtained were 283.8 ± 28.1 μg L(-1) for A. carbonarius and between 1.7 ± 0.1 μg L(-1) and 16.5 ± 12.8 μg L(-1) for A. steynii strains. While the optimal conditions of growth for A. carbonarius and A. steynii are 28°C and 0.98 a w, the optimal production of OTA was observed at 0.99 a w for both A. carbonarius and A. steynii but at 22°C and 28°C, respectively. Except in one sample, all the aniseed samples analysed were negative for OTA natural contamination. This study demonstrates that aniseed can be a matrix capable to contamination with OTA, at least produced by A. carbonarius and A. steynii strains, regardless of the antimicrobial properties of aniseed essential oil.