Effectiveness of hand sorting, flotation/washing, dehulling and combinations thereof on the decontamination of mycotoxin-contaminated white maize

Abstract

Maize is one of the major staple foods of Sub-Saharan Africa and is consumed as whole or dehulled grain. In this region, where the environmental conditions favour fungal growth and mycotoxin production, the majority of the population are subsistence consumers who, unfortunately, have little or no access to mycotoxin testing of their food. In an attempt to develop feasible reduction strategies in dietary mycotoxin exposure of the population, a three-factorial design experiment was conducted to examine and compare the efficacy of hand sorting, flotation, dehulling and combinations thereof in removing naturally occurring aflatoxins, fumonisins, nivalenol, deoxynivalenol and alternariol in shelled white maize. Regression analysis was used to determine the significant (p < 0.05) process variables on the removal of mycotoxins from the maize. Results from this experiment indicated that hand sorting had the greatest effect on mycotoxin removal, while flotation yielded the least effect. In particular hand sorting left < 6% of aflatoxin B1 and < 5% of fumonisin B1. Based on these results, hand sorting of maize grains is being recommended as a last line of defence against mycotoxin exposure among subsistence consumers.

Graphical Abstract

Keywords:

• shelled white maize
• hand sorting
• flotation/washing
• dehulling
• mycotoxin decontamination

Acknowledgements

This research benefitted from a statistical consult with Ghent University FIRE (Fostering Innovative Research based on Evidence). The invaluable technical assistance provided by L. Singano, T. Mhango, H. Mbalame, C. Gadaga, D. Kalima, D. Bwanamiri, M. Kalitsiro, E. Moyo, C. Tchuwa and O. Goodson is greatly appreciated.

Additional information

Funding

VLIR-UOS (Flemish Inter-University Council–University Development Cooperation), the Republic of Malawi (Ministry of Agriculture and Food Security), the World Bank, and the Norwegian Ministry of Foreign Affairs (the latter three jointly provided their support through Agriculture Sector Wide Approach support project (ASWAp-SP)) are acknowledged for co-financing the first author’s doctoral studies.