Determination and Comparison of Total Aflatoxin Levels in Groundnuts from Four Major Markets in Lagos State, Nigeria

Abstract

Aflatoxins (Aspergillus flavus toxins) are poisonous substances produced by some fungi on crops, foods, and feeds. The study was carried out to determine and to compare total aflatoxin levels in groundnuts sold in Lagos markets, Nigeria. Microbiological and toxicology tests were carried out on raw, boiled, and roasted groundnuts from the same source. The microbiological test was carried out to detect the fungi that produce aflatoxins as their secondary metabolite. The groundnuts samples were cultured on Potato Dextrose Agar (PDA). The isolates were identified using standard microbiological methods, characteristics such as presence of spores, shape, colour of spores and presence of septa were used in identification. Aspergillus flavus (75%; percentage of occurrence) was the most frequently isolated fungus from the groundnut samples. The other contaminant isolated from the samples were Aspergillus niger (25%). The toxicology analysis was carried out to determine the production of aflatoxins and the level present in the groundnut. This was carried out using a Romer Mycosep Column kit for aflatoxin to clean-up, and High-Performance Liquid Chromatography (HPLC) to detect the aflatoxins and determine the levels. Total aflatoxins were detected in the groundnuts, and they ranged between 0.36 ppb and 0.42 ppb. The levels of total aflatoxins were not beyond the regulatory standard of National Agency for Food and Drugs Administration and Control- NAFDAC (for ready to eat food, 4µg/kg while food that will still undergo processing 20µg/kg). Thus, the groundnut samples from the four markets are fit for consumption.