Characterization of aflatoxin producing Aspergillus flavus from food and feed samples

Area of Science:

• Food microbiology
• Mycotoxicology
• Agricultural science

Background:

• Aspergillus flavus is a significant producer of aflatoxins, contaminating various agricultural commodities during field cultivation or storage.
• Aflatoxins pose serious health risks to humans and animals, necessitating monitoring and control strategies.

Purpose of the Study:

• To isolate and identify Aspergillus flavus from feed and grain samples.
• To assess the aflatoxigenic potential of the isolated Aspergillus flavus strains.
• To determine the prevalence of specific aflatoxin biosynthesis genes in the isolates.

Main Methods:

• Isolation and morphological identification of presumptive Aspergillus flavus from 30 feed and grain samples.
• Confirmation of Aspergillus flavus identity using DNA sequencing of the 5.8s rDNA gene.
• Detection and quantification of aflatoxin production in vitro.
• Screening for the presence of seven key aflatoxin biosynthesis genes (aflR, aflS, aflQ, aflP, aflD, aflM, and aflO).

Main Results:

• Fifteen presumptive Aspergillus flavus isolates were obtained, all confirmed by DNA sequencing.
• All isolates were found to be aflatoxigenic, with 11 producing both aflatoxin B1 and B2.
• Over 90% of isolates produced aflatoxin B1 (7-22 μg/g agar), and all possessed at least three toxigenic genes.
• Genes aflP and aflQ were the most prevalent among the screened toxigenic genes.

Conclusions:

• The study confirms the widespread presence of aflatoxigenic Aspergillus flavus in feed and grain samples.
• The identified isolates pose a significant risk to public health due to potential aflatoxin contamination of agricultural commodities.
• Implementing proper harvest and storage management practices is essential to reduce aflatoxin risks in feed and grains.