Postharvest practices and aflatoxin content of cowpea (Vigna unguiculata L. Walp.) grain in Burkina Faso

Abstract

Cowpea is one of the most important crops in addressing food insecurity in less developed rural communities. However, due to certain inappropriate production and storage conditions, this crop is likely to be contaminated by fungi capable of producing mycotoxins. Hence, the objective of this study was to determine on post-harvest processing for cowpea grains in the three climatic zones, Sahelian, Sudano-Sahelian and Sudanian, of Burkina Faso and to assess the aflatoxin B₁, B₂, G₁ and G₂ content of these grains. A questionnaire was administered to 69 producers to determine the post-harvest processing methods of cowpea grain. The questionnaire was supported with direct observations. Post-harvest handling of cowpea grains by producers, predominantly female (74.4%), revealed that pod drying was on plastic sheets (39.13%), plastic bags (13.04%), terraces (36.23%), on the ground (4.35%), on the roof of sheds (4.35%) or on the roof of houses (2.9%). Whereas the main materials used for grain storage were sealed cans (49.28%) and Purdue Improved Crop Storage (PICS) bags (26.09%). Insects (36.23%) and fungi (10.14%) were the main biotic constraints reported. The aflatoxin contents of cowpea grain samples collected were relatively low (0.02 μg kg⁻¹ to 2.56 μg kg⁻¹) compared to the limit values set by the codex (0.5–15 μg kg⁻¹) for foodstuffs. The study provides valuable insights into mycotoxin risks, offering guidance for regulatory measures. Its findings are applicable to other regions of Sub-Saharan Africa and developing areas, presenting practical solutions to enhance post-harvest management and address contamination challenges.