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Detection of aflatoxigenicity of Aspergillus flavus , based on potential gene marker, from food and feed samples
Author(s) -
Khalid Saima,
Hussain Noshal,
Imran Muhammad
Publication year - 2018
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/jfs.12448
Subject(s) - aflatoxin , aspergillus flavus , biology , polymerase chain reaction , food science , aspergillus , food contaminant , microbiology and biotechnology , gene , biochemistry
In this study, the incidence of aflatoxigenic strains of Aspergillus flavus was evaluated in cattle feed, water, and milk from three districts of Northern Punjab region of Pakistan. In total, 39 of the hundred samples collected were found contaminated by A. flavus . Specifically, the incidence of A. flavus was 54.28 %, 53.3 %, and 11.42 % in feed ( n = 35), water ( n = 30), and milk ( n = 35) samples, respectively. The UV method indicated aflatoxigenic potential in 62 % of strains, and the ammonia vapor test showed 54 % of samples to be positive for aflatoxin production. Polymerase chain reaction detection of aflatoxin producing cluster of A. flavus was done by identifying four structural genes, that is, nor‐1 , ver‐1 , omt‐A , afl‐R . It is inferred that omt‐A and afl‐R genes were regarded as potential markers for aflatoxins production. Therefore, this study proved that omt‐A could be used for rapid detection of potential aflatoxigenic strains in feed, water and food products. Practical applications In this study, the isolates of Aspergillus flavus were investigated for their aflatoxigenic nature using cultural (fluorescence under UV‐light and NH 4 OH vapor induced color change test) and molecular (PCR) methods. The UV test is more sensitive than the ammonia test; however, comparable results from both methods strengthened our confidence in the findings. PCR results indicated the omt‐A and afl‐R genes as potential markers for aflatoxins biosynthesis because these genes were amplified in all those strains that were regarded as aflatoxigenic based on cultural methods for aflatoxin detection. Thus, the combined use of cultural and molecular methods used in this study can provide a cheaper and faster way to detect aflatoxigenic A. flavus in food and feed samples in developing countries.