Characterization of aflatoxin producing Aspergillus flavus from food and feed samples.

Md Fakruddin,Monzur Morshed Ahmed,Md Nur Hossain,Abhijit Chowdhury

doi:10.1186/s40064-015-0947-1

Md Fakruddin, Monzur Morshed Ahmed + Show 2 more

Open Access

https://doi.org/10.1186/s40064-015-0947-1

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Abstract

Aspergillus flavus is one of the major producers of aflatoxin and can contaminate wide range of agricultural commodities either in field or in storage. 15 presumptive Aspergillus flavus has been isolated from 30 feed and grain samples. All the isolates were morphologically similar to Aspergillus flavus type strains. All the isolates were found to be aflatoxigenic. DNA sequencing of 5.8 s rDNA confirmed all of them to be Aspergillus flavus. Only 1 isolate possessed all the seven toxigenic gene (aflR, aflS, aflQ, aflP, aflD, aflM, and aflO) while aflP & aflQ were most prevalent in the isolates. All the isolates possessed at least three toxigenic genes. Toxin producing ability in solid culture media showed that 11 isolates isolates were able to produce both aflatoxin B1 & B2. More than 90% isolates produced aflatoxin B1 ranging 7–22 μg/g of agar. This study alarms us about the potential risks of Aspergillus flavus to public health if contaminate agricultural commodities such as grains or raw materials such as poultry feed. Proper harvest and storage management is required to reduce the risk of aflatoxin in feed and grains.

Highlights

One of the most important ubiquitous fungal species in tropical environments is Aspergillus flavus that can be found in soil and other substrates (Powell et al 1994)
Different mycotoxins have been reported as contaminant of poultry feed, most important of which are aflatoxins (B1, B2, G1, G2) and Ochratoxin A (OTA) (Gentles et al 1999)
Isolation 15 presumptive Aspergillus flavus strains has been isolated from the 30 samples (15 feed and 15 grain sample; grain sample include nuts and pulses; all the samples were collected from local market) analyzed (Figure 1)

Summary

Introduction

One of the most important ubiquitous fungal species in tropical environments is Aspergillus flavus that can be found in soil and other substrates (Powell et al 1994). Aspergillus flavus is reported to be associated with many diseases of human, most severe of which is invasive aspergillosis. It can cause diseases in insects (Campbell, 1994) as well as in crops (such as maize, rice, peanuts etc.). Agricultural products including cereals e.g. maize, wheat, sorghum and by products thereof and variety of oilseeds are major constituents of poultry feed (Okoli et al 2006). Agricultural commodities if contaminated with toxigenic fungi like A. flavus producing mycotoxin can be injurious for animals and human health. Different mycotoxins have been reported as contaminant of poultry feed, most important of which are aflatoxins (B1, B2, G1, G2) and Ochratoxin A (OTA) (Gentles et al 1999). Aflatoxins are the most studied group of mycotoxins which apart from producing clinical toxicosis

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