Abstract

Aflatoxins are potent mycotoxins, which are produced by toxigenic Aspergillus species including Aspergillus flavus and Aspergillus parasiticus. The goals of this study were to characterize Aspergillus fungus isolated from rice bran and to determine the correlation between Aflatoxin B₁ (AFB₁) production and Aspergillus contamination in the samples. Thirty rice bran samples were collected from different regions of Mazandaran province, northern Iran. Samples containing 15 specimens were conserved for one year in the storage and the other one was not subjected to storage. Mycological analysis of rice bran was performed and AFB₁ was purified from the samples and quantified by high performance liquid chromatography (HPLC) method with fluorimetry detection. The results of this study showed that almost all collected samples contained AFB₁. The averages of AFB₁ in new and old rice bran samples were found to be 5.07 and 6.81 µg/kg, respectively. No significant difference was obtained between AFB₁ value in new and old samples. In addition, the correlation between culture results and aflatoxin production were significantly observed only in old samples (P<0.05). The most frequent isolatedAspergillus species were Aspergillus terreus, A. flavus, Aspergillus niger, A. parasiticusand Aspergillus fumigatus. In conclusion, these results confirmed that rice bran could be contaminated with AFB₁ and toxigenic Aspergillus species and human beings are in danger of been affected by contaminated rice products.

Key words: Aflatoxin B₁, rice bran, toxigenic Aspergillus species.