Regulatory Gene, aflaR Identification of Aflatoxigenic Moulds and total Aflatoxin estimation in Digitaria exilis and Digitaria iburua sold within Kaduna Metropolis

Abstract

Author: Joseph Reuben Wartu., Sani Sambo Datsuquai Mohammed,  John Idakwoji   and   Tessy Bamai

Contamination of Digitaria sp by aflatoxigenic strains could pose a serious health threat to food safety.  In this study, a design is made with the aim of screening and characterizingmoulds isolated from Digitaria iburua and Digitaria exilis sold within the Kaduna metropolis. Seventy samples of Digitaria sp were obtained from four outlets of some markets within the Kaduna metropolis. The proximate values were determined following standard procedures. Isolation and characterization of the moulds were done using standard techniques. Polymorphic technique and regulatory gene aflaR were employed to identify the aflatoxigenic moulds isolated from the samples. Analysis of the aflatoxin content of the samples was carried out using Enzyme-Linked Immunosorbent Assay (ELISA) technique. This research has recorded proximate values determined for Digitaria sp as follows: moisture content 6.90%, protein 11.10 %, ash 3.90 %, fats 3.9 %, and carbohydrate content 74.16 % for Digitaria iburua. Digitaria exilis presented a moisture content of 7.3 % while other proximate contents were protein (10.2%), ash (3.21%), fats (2.3%), and carbohydrate content (76.99%) %. The moulds; Aspergillus flavus, Rhizopus stolinifer, Fusarium sp, Saccharomyces cerevisae, Aspergillus parasiticus, Aspergillus niger, mucor sp and Penicillium sp were isolated from both Digitaria exilis and Digitaria exilis with Aspergillus flavus having the highest frequency of occurrence. The total viable mould count for each sample location ranged from 1.5X10³ – 2.8X10³ CFU/g, 2.3X10³-3.1X10³ CFU/g, 2.6X10³-5.4X10³ for Kawo, Sabo and Central markets respectively. Analysis of the total aflatoxin content of the seventy samples showed a prevalence of 16.7 %. There is a need to sensitize farmers and consumers on the occurrence of the toxin and also the need to develop a resistant variety is hereby advocated.