Study of the Ochratoxin A effect on Aspergillus parasiticus growth and aflatoxin B1 production

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species. Ochratoxin A (OTA) is a metabolite of Aspergillus ochraceus and Penicillium verrucosum. AFB1 and OTA are amongst the most frequent combinations of mycotoxins found in plant products. Thus, synergistic effects or interactions between the two mycotoxins could be taking place. The aim of the present study was to investigate the effect of OTA on Aspergillus parasiticus growth and AFB1 production in yeast extract sucrose (YES) medium at concentrations of 0.16, 1.6 and 16 ng OTA flask−1. The AFB1 extracted from cultures and purified with immunoaffinity columns was then quantitated by HPLC. The recovery and detection limit of the method were 95.3% and 0.02 ng AFB1 mL−1, respectively. Maximum AFB1 productions in cultures with OTA were observed from 9 to 12 days (76.09–82.52 ng AFB1 flask−1) while in control cultures (without OTA) maximum production (197.2 ng AFB1 flask−1) was observed on 14th day. Maximum AFB1 levels in cultures with OTA were reduced by a percentage of 58–61% compared to control cultures. Furthermore AFB1 levels in cultures with OTA were practically (92%) degraded after 18 days of incubation. Conclusively when OTA is present the production of AFB1 by A. parasiticus in YES medium is inhibited.