Aflatoxin variations in maize flour and grains collected from various regions of Kenya

摘要

In Kenya, maize remains an important staple food in every household. Unfortunately, the fungus Aspergillus flavus can infect the maize and produce aflatoxins. While government efforts to remove contaminated maize from circulation are well intentioned, there remain concerns that consumers are still being inadvertently exposed to aflatoxin. The aim of this study was to sample maize in different parts of Kenya and determine if consumers were inadvertently being chronically exposed to aflatoxins. Seventy-five maize samples and 27 samples of maize flour from three regions of Kenya (Nairobi, Eastern and Western) were analysed using an ELISA assay followed by microtiter plate reader (Neogen model) where the optical density of each microwell was read using a 450nm filter. There was a significant difference in aflatoxin levels in maize grains between the three regions and five stores (P0.05). Samples from Eastern Kenya had the highest contamination at 22.54±4.94 ppb, while those from Nairobi had the lowest (7.92±1.57 ppb). There was no significant difference in the total aflatoxin in maize flours from Nairobi, Western and Eastern regions (P0.05) at 95% confidence interval. Aflatoxin in maize flours were slightly above international upper limit of 5ppb but all the results were lower than the Kenya standard whose upper limit is 10ppb, indicating good manufacturing practices (GMP) by the millers. Samples of maize flours from Eastern Kenya had the highest aflatoxins concentrations at 6.98± 0.53 ppb. In summary, the study found aflatoxin contamination in maize grains especially in Eastern Kenya. The study concluded that measures put in place by government agencies for millers appear to be working. However, samples of maize grains showed variation among the regions and between stores, perhaps due to storage practices, with some levels far exceeding health limits. Due to higher levels of aflatoxin contamination in maize grains in relation to maize flours, the government and relevant stakeholders need to establish further measures to protect consumers.