Post harvest handling practices and aflatoxin contamination levels of cassava flour samples from Alur and Acholi cultural settings, Northern Uganda

Abstract

Aflatoxins are toxic mycotoxins produced by fungi like Aspergillus flavus and A. parasiticus, prevalent in warm, humid regions, particularly Sub-Saharan Africa. In Uganda the primary aflatoxins of concern are AFB1, AFB2, AFG1, AFG2, AFM1, and AFM2 (Lukwago et al., 2019). Aflatoxin-producing fungi can contaminate crops in the field, harvest time and postharvest period. Cassava is a staple food in Northern Uganda, particularly among Alur and Acholi communities, but it faces high risks of aflatoxin contamination due to traditional postharvest handling practices. This study assessed post-harvest handling practices and aflatoxin contamination levels of cassava flour samples from Alur and Acholi cultural settings, Northern Uganda. The study identified and compared the traditional cassava processing methods in the two cultural settings, determined the level of aflatoxins contamination in cassava flour, and evaluated the influence of specific post-harvest handling practices on contamination levels. A cross-sectional study design was employed, involving the collection of 36 cassava flour samples from Nebbi Municipality (Alur) and Gulu City (Acholi). Samples were analyzed using Thin Layer Chromatography (TLC) at Analytical Biosciences Laboratory, Makerere University. Data was collected using structured questionnaires, field observation, and interviews, and analyzed using SPSS, Excel, and descriptive statistics. Results showed that all Cassava flour samples were positive for Aflatoxin B, but negative for Aflatoxin G, 66.67% of cassava flour samples exhibited very high levels of aflatoxin B contamination, mainly associated with heap-mold fermentation practiced in Alur culture. Storage duration was found to have a statistically significant association with aflatoxin contamination levels (χ² = 8.701, p = 0.013 where X2 , the chi-square value is deviation of observed data from expected data. And P-value is probability of obtaining X2 ). The study also established that heap fermentation, prolonged storage, and poor drying methods increased contamination risks. Conversely, the chips drying method used in Acholi culture, use of tarpaulin drying platforms, shorter drying durations, and plastic storage containers reduced aflatoxin risks. The study recommends adoption of safer drying and storage methods, limiting storage duration to under one month, promoting chips drying, and strengthening post-harvest training and policies to safeguard cassava consumers against aflatoxin-related health risks