Aflatoxin in Food: What Role for Biotechnology? - OFAB

Toxicological manifestation: include cancer, mutagenicity, birth defects (teratogenic) and
estrogenic, gastrointestinal, urogenital, vascular, kidney and nervous system disorders.
The compromised immune response that accompanies chronic exposure to some mycotoxins
reduces resistance to infectious disease and may be the most important and the most
underappreciated of the health problems associated with mycotoxins
Toxicological effects on children include reduction of growth. Development of children exposed
to aflatoxins may reduce quality of life and limit an individual’s ability to reach their potential.
Aflatoxin Pathogenicity
Dr Maina discussed some of the diseases inflicted by Aspergillus.
Toxicological manifestations inflicted by the fungus include cancer, birth defects,
gastrointestinal, urogenital, vascular, kidney and nervous system disorders. He affirmed that the
compromised immune response that accompanies chronic exposure to some mycotoxins reduces
resistance to other infectious diseases as well. He was of the opinion that the later is one
pathogenicity aspect which may be the most important and the most underappreciated of the
health problems associated with mycotoxins.
Exposing some of the strains responsible to cause illnesses, Dr Maina listed A. flavus as second
only to Aspergillus fumigatus among Aspergillosis strains causing Aspergillosis. He added A.
flavus as the most frequently reported Aspergillus species causing keratitis, an inflammation of
the eye cornea.
Detection of Aflatoxigenic fungi
Dr Maina shared the methods used so far in detecting Aflatoxigenic fungi, including the use of
UV light, Polymerase Chain Reaction, Transcription Polymerase chain reaction and Multiple
Transcription Polymerase chain reaction
Detection of Mycotoxigenic Fungi by Fluorescence under UV light
Aflatoxins can be identified in colonized corn kernels by viewing under UV light.
However, De Maina pointed out that the detection of Aflatoxins as judged by fluorescence of
fungal colonies is not conclusive, in that non-aflatoxigenic strains of Aspergilli, such as A.
parasiticus and A. niger fluoresce also under UV. This could lead to wrong interpretation and
conclusion that there is presence of Aflatoxins. Further diagnostic test for the presence of
Aflatoxins in fungal colonies can be determined by observation of continued phosphorescence of
Aflatoxins at room temperature, after switching off the UV light, the fluorescence will last for
0.5 seconds. Without the UV light, Non-Aflatoxigenic Aspergilli do not phosphoresce. With the
help of pictures, Dr Maina took time to illustrate, by photos, the difference between the
appearance of non-aflatoxigenic and Aflatoxigenic colonies under UV light and after switching
off the UV lamp.
Detection of Mycotoxigenic Fungi by Polymerase Chain Reaction
Another way to detect mycotoxins was found to be by Polymerase Chain Reaction (PCR).
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