Assessment of Total Aflatoxins Level of Two Major Nuts Consumed in Makurdi Benue State, Nigeria

Abstract

The main aim of this study was to determine the total aflatoxin (TAF) contents of roasted cashew nuts (Anacardium occidentale), and the roasted, hulled and dehulled groundnuts (Arachis hypogaea L.) sold and consumed in the major public areas of Makurdi Benue State, Nigeria. The items were sampled from 10 different locations based on human traffic densities and sellers of the product and then analysed for TAF contents using direct competitive Enzyme-linked Immunosorbent Assay (ELISA) method. In the roasted cashew nuts, TAF was only dectected in samples collected at two of the locations; Wadata New Garage (0.10 µg/kg) and High-Level (0.40 µg/kg) but not detected in samples collected at the eight others. However, the detected levels were below the maximum permissible limits (MPL) of 4 µg/kg set by EU and 10.0 µg/kg set by CAC and NAFDAC, Nigeria for ‘ready to eat’ food substances. In the roasted groundnuts, levels of TAF higher than the indicated MPL were recorded in samples collected at Modern Market (12.00 µg/kg) and Railway Market (> 20.00 µg/kg) while similar result at North Bank (5.60 µg/kg) only exceeded the EU MPL. Only samples of hulled groundnuts collected at High-Level and Wurukum recorded TAF levels of 0.20 µg/kg. Dehulled groundnuts sampled at Modern market (13.10 µg/kg) and Railway market (> 20.00 µg/kg) recorded higher TAF levels than CAC and NAFDAC MPLs while similar result at North Bank (6.20 ppb) only exceeded the EU MPL. Apart from the dehulled groundnuts samples collected at the Modern market sample location which recorded a moisture level of 5.84 %; all the other samples had moisture levels below the recommended maximum safe limits of 5.80 % for stored groundnuts and cashew nuts. The results of microbial counts showed that total mesophilic bacteria varied between < 1.0 x 101 to >1.0 x 102 CFU/L, fungi varied between < 1.0 x 101 to > 1.0 x 101 CFU/L while E.coli counts varied between 0.00 to 0.43 CFU/L. The microbial contamination was generally low. However, prolonged consumption of the TAF-contaminated nuts is possible in the study area due to the rising food insecurity of majority of the populace. The chronic exposure therefore, presents health concern of aflatoxicosis.