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

ABSTRACT

The aim of this study was to assess the total aflatoxin (TAT) contents of roasted, dehulled and hulled groundnuts (Arachis hypogaea L.) and of roasted cashew nuts (Anacardium occidentale), sold and consumed in some public areas of Gboko metropolis of Benue State, Nigeria. The items were sampled from 5 different locations based on human traffic densities and sellers of the product and then analysed for TAT contents using direct competitive Enzyme-linked Immunosorbent Assay (ELISA) method. In the roasted cashew nuts, TAT was only detected in samples collected at two of the sampling sites; Mechanic Site/Adekaa (>20.00 µg/kg) and Gboko Main Market (0.30 µg/kg) but not detected in samples collected at the three others (Gboko motor park, Abagu and Tipper Garage). Nevertheless, the detected levels at Gboko Main Market were below the maximum tolerable limits (MTL) of 4 µg/kg set by EU and 10.0 µg/kg set by CAC and NAFDAC, Nigeria for ‘ready to eat’ food substances unlike the situation at the Mechanic Site/Adekaa sampling location. In the roasted groundnuts, levels of TAT higher than the indicated MTL were documented in samples collected at Tipper Garage (12.20 µg/kg) and Abagu (5.70 µg/kg) only exceeded the EU MTL, while the results at Gboko motor parks (2.00 µg/kg), Gboko main market (1.30 µg/kg) and Mechanic site/Adekaa (0.50 µg/kg) were below the EU MTL. Samples of hulled groundnuts collected at Gboko main market recorded TAT levels of 0.10 µg/kg while at Mechanic site/Adekaa it was not detected. Dehulled groundnuts sampled at Gboko Main market (0.40 µg/kg) and Mechanic site/Adekaa (0.20 µg/kg) recorded TAT levels within CAC and NAFDAC MTLs. The dehulled groundnuts samples collected at the Tipper Garage sample location, which recorded a moisture level of 4.20 %; yet among the rest of all the other samples had moisture levels below the recommended maximum tolerable limits of 5.80 % for stored groundnuts and cashew nuts. The results of microbial counts revealed that total mesophilic bacteria ranged between < 1.0 × 10¹ to >1.0 × 10² CFU/L, fungi varied between < 1.0 ×10¹ to > 1.0 × 10¹ CFU/L while E.coli counts varied between 0.00 to 0.32 CFU/L. The microbial contagion was generally low. Nevertheless, prolonged feasting on the aflatoxin-contaminated nuts is possible in the study area due to the rising food insecurity of majority of the masses. The chronic and acute exposures therefore, presents health concern of aflatoxicosis.