Surveillance of aflatoxin levels in maize (Zea mays L.) grains sold in some major markets of Kaduna State, Nigeria

Abstract

Aflatoxin contamination in maize is a significant food safety challenge in Nigeria, causing post-harvest losses and posing a threat to public health. This study evaluated the levels of aflatoxin contamination in maize grains sold in five major markets (Samaru, Sabon Gari, Railway, Central Market, and Tudun Wada markets) in Kaduna State. The grains were stored in sacks for 9–11 months before being marketed. Maize grains (one kilogram) were randomly collected from two cluster points in the selected markets in March 2023. Grains were obtained from five locations (vendors) in each market cluster. Aflatoxin was extracted from ground samples using the enzyme-linked immunosorbent assay (ELISA) protocol. The mean aflatoxin levels in maize grains sold in the markets ranged from 6.53±0.7 μg/kg to 60.87±1.87 μg/kg. Analysis of variance (ANOVA) of the aflatoxin levels showed a significant difference (p≤0.05) across the sampled locations. Mean aflatoxin levels in samples from Samaru 1, Samaru 2, and Kaduna Central Market 1 were 9.27±0.37, 6.53±0.7, and 9.67±0.55 μg/kg aflatoxin levels, respectively. These levels were within the permissible aflatoxin limit of the Standard Organization of Nigeria (10.00 μg/kg). Aflatoxin levels in all the samples were higher than the permissible limit of the European Union/World Health Organization limit (4.00μg/kg). Thus, limiting exports of our commodities. Even though the moisture contents recorded were within the recommended level for storage, the grains were still contaminated with aflatoxin. The incidence of aflatoxin contamination in the grains could therefore be linked to improper farmers' awareness, poor storage practices, and weather conditions. In conclusion, this study showed a high level of aflatoxin contamination (highest mean = 60.87±1.87) in maize grains sold in some major markets in Kaduna. Only maize grains sampled at Samaru and Kaduna Central (Cluster 1) markets are within the permissible limits and acceptable for consumption in Nigeria.