EVALUATION OF MOULDS CONTAMINATION OF CEREALS AND LEGUMES SOLD IN DUTSINMA METROPOLIS AND THEIR AFLATOXIN PRODUCTION POTENTIAL

Abstract

Contamination of food materials by aflatoxigenic moulds put the health and well-being of consumers of such food materials at risk of hepatocellular carcinoma. The aim of this study was to isolate and identify moulds capable of producing mycotoxins from maize millet, guinea corn, groundnut and groundnut cake sold to consumers within Dutsinma metropolis, Katsina State of Nigeria. Fungal isolation was done using the direct plating of serially diluted samples of the cereals and legumes, and direct plating technique of surface-sterilized samples of same on potato dextrose agar. Fungi colonies were purified by sub-culturing on fresh potato dextrose agar. The Isolates were identified by comparison of colony morphology and microscopic characteristics with standard reference guide for identification. Determination of aflatoxin producing potential of fungal isolates was carried out using fluorescence under UV-light at 365nm. A total of 124 fungi were isolated and identified. Fifty five (55) of the isolates were identified as Aspergillus Spp., giving a prevalence of 44.4%, and 69 as non-aflatoxigenic moulds (55.6%). Among the Aspergillusgroup, A.niger had the highest prevalence (35.0%), followed by A.flavus (31.7%), A.fumigatus (15.0%). A.lentulus (10.0%) were less prevalent. Determination of aflatoxin production potential using UV-light, showed that 15 isolates fluoresced blue, 21 fluoresced green and 15 fluoresced blue/yellow (reverse plate), indicating potential production of various toxins including aflatoxins B1, B2, G1, and G2. The results showed that cereals and legumes sold in Dutsinma metropolis were highly contaminated with Aspergillus Spp., which showed potential for aflatoxin production.