Occurrence of Aflatoxins in Maize and Maize Products from Selected Locations of Tanzania and the Effects of Cooking Preparation Processes on Toxin Levels

Abstract

The production and storage of food crops in different countries is affected by aflatoxins
contamination, which are known to be carcinogenic and mutagenic to human beings and domestic
animals. This study investigated on the occurrence of aflatoxins in maize products and the effects
of cooking preparation processes on their concentrations. The maize samples were collected from
fields, farmers' stores and markets of selected locations in Tanzania (i.e., Kongwa and Njombe
districts). Extracted samples were analyzed for aflatoxins using high performance liquid
chromatography. The concentrations of aflatoxins in maize and maize products ranged from below
detection limit to 9.99 ± 1.43 μg/kg and 9.99 ± 0.14 μg/kg for Njombe and Uwemba wards,
respectively. Whereas those collected from Kibaigwa ward in Kongwa district ranged from 2.87 ±
0.02 μg/kg to 10.26 ± 0.46 μg/kg. The levels in cooked maize products were lower than the
uncooked maize products. The mean concentrations of total aflatoxins in cooked maize products
were 0.45 ± 0.05 μg/kg for stiff porridge prepared from dehulled maize flour, 1.39 ± 0.02 μg/kg
for stiff porridge prepared from undehulled maize flour, and 0.584 ± 0.06 μg/kg for maize meal
(kande). Generally, the levels of aflatoxins were below the maximum acceptable limits set by
WHO except for some samples from Kibaigwa market which were slightly above the set limits.

Keywords: Aflatoxins; High Performance Liquid Chromatography; Maize; Fungi.