Determination of Aflatoxin Levels in Raw Groundnuts From Markets in Lusaka District,Zambia

Abstract

Groundnuts, one of the most susceptible crops to aflatoxin (AF) contamination, are widely produced and consumed in Zambia. Previous studies have reported high levels of AFs in groundnuts produced in Zambia. However, there has been no study on the levels of AFs in groundnuts sold in different market types. This cross-sectional study was designed to determine the levels of AFs in raw groundnuts sold in Lusaka District’s markets as well as identify factors associated with increased AF presence. Raw groundnut samples were collected from open markets and supermarkets in Lusaka District and analyzed for AF presence using high performance liquid chromatography (HPLC). A questionnaire was also administered to the groundnut’s venders to investigate factors contributing to increased levels of AFs in groundnuts. Of the 92 groundnut samples, 51 (55.4%; 95% CI: 44.9 ‒ 65.4) tested positive for presence of AF. The overall median and geometric mean  standard deviation (SD) concentration for AF were 0.23 parts per billion (ppb) (range: 0.014 to 48.67 ppb) and 0.43  9.77 ppb, respectively. The presence of AF was almost the same in both types of markets. However, the highest concentration was recorded in a sample collected from a supermarket (48.67 ppb). Despite this, the association between market type and presence of AFs was not statistically significant (Pearson Χ2 = 0.0587, p = 0.809). Of 51 samples that tested positive to AF, 6.5% and 12% were above the maximum permissible limits (MPLs) set by the Codex Alimentarius Commission and European Union standards, respectively. There was a significant difference in the levels of AF between Chalimbana and Kadononga (p<0.0001), and also Chalimbana and Makulu red (p<0.0001). Chalimbana was the most at risk of AF contaminations, when compared to other groundnut varieties. The high level of AFs in raw groundnuts from both supermarket and open market samples constitutes a health hazard for the population of Lusaka district. Therefore, intervention strategies that reduce the level of AFs contamination in groundnuts should be given priority. Keywords: Aflatoxin; Groundnut; Risk factors; Zambia