Study of fungi and their toxigenic potential isolated from wheat and wheat bran

Abstract

The present study was designed to investigate the fungi and their toxigenic potentials isolated from the wheat and wheat brans. A total of 67 samples of wheat and 17 samples of wheat bran were collected from Faisalabad district of Pakistan. Forty-five (67.16%) samples of wheat yielded fungi. Frequency distribution based on total samples, Aspergillus was the highest (44.77%) genus followed by Penicillium, Fusarium and Alternaria. Penicillium verucosum (30.64%) was the most frequently isolated species followed by A. niger aggregates, A. flavus, A. parasiticus, P. chrysogenum, A. ochraceous, A. carbonarius and A. fumigatus. Among Aspergilli, A. niger aggregates (46.67%) were most frequently isolated species. Out of 30 Aspergilli isolates from wheat samples, 17 (56.66%) were found toxigenic. AFB1 produced by aflatoxigenic Aspergilli varied from 1.44 to 836.3 ng/g, while ochratoxin A levels varied from 0.037 to 15 045 ng/g. Among Penicillium species, P. verrucosum (63.15%) were found ochratoxigenic and OTA levels were varied from 7.31 to 8400 ng/g. In wheat bran, 10 (58.82%) samples yielded fungi. Based upon total samples, frequency distribution of Aspergillus (35.28%) was the highest followed by Penicillium and Fusarium. Similar pattern was observed in relative density of isolates. A. niger aggregates and P. verrucosum were predominant species (23.07%) isolated from wheat bran. Among Aspergilli, A. niger aggregates (50%) were the most frequently isolated species followed by A. flavus, A. fumigatus and A. ochraceous (16.67%) each. The OTA levels of fungi isolated from wheat bran varies from 0.292 to 2500 ng/g. Isolation of toxigenic A. niger aggregates from wheat indicates that these species should be considered as possible contributors of OTA contamination in wheat and its by-products in Pakistan.

Keywords:

• Aspergillus
• ochratoxin A
• aflatoxins
• wheat
• wheat-bran
• penicillium

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.