Storage structures and mycotoxin exposure: A comparative study of aflatoxin risk in maize and groundnuts

This study investigated aflatoxin accumulation in maize and groundnuts stored in concrete “Safe Elephant” granaries compared to traditional pole-and-reed granaries in the Kakumbi and Mnkhanya chiefdoms of eastern Zambia. The aim was to evaluate the efficacy of both storage systems in maintaining food safety and grain quality. Samples were collected from four concrete and four traditional granaries, stored under consistent conditions, and analyzed using High-Performance Liquid Chromatography at the National Science Laboratory of Zambia. Results revealed significantly higher aflatoxin levels in concrete granaries, with concentrations reaching up to 6.05 ppm, compared to as low as 0.5 ppm, and occasionally undetectable, in traditional granaries (χ² = 14.82, df = 1, p < 0.001). Aflatoxin accumulation in maize increased with storage duration, ranging from 0.60 ppm after two months to 6.05 ppm after five months (χ² = 10.94, df = 2, p = 0.0042). Groundnuts were more susceptible than maize, accumulating up to 1.00 ppm, likely due to their higher oil content (χ² = 7.82, df = 1, p = 0.0052). Adoption of concrete granaries remained low, with only 15% in use in Kakumbi and 25% in Mnkhanya (χ² = 0.83, df = 1, p = 0.361), largely due to cost, lack of training, and perceived grain quality issues. The study concludes that traditional granaries, when protected from wildlife, offer safer storage. Recommendations include enhancing ventilation in concrete granaries and adopting digital monitoring technologies to control internal storage conditions.

aflatoxin, storage, granary, traditional granaries, food safety

1. Abdel-Hadi, A., Schmidt-Heydt, M., Parra, R., Geisen, R. and Magan, N., 2012. Systems approach to model the relationship between aflatoxin gene cluster expression, environmental factors, growth and toxin production by Aspergillus flavus. Journal of the Royal Society Interface, [online] Available at: https://doi.org/10.1098/rsif.2012.0053. [Google Scholar] [Crossref]

2. Adejumo, B.A., 2013. Development of a 350 kg double-walled insulated metallic silo for tropical climate. Greener Journal of Scientific Engineering and Technology Research, 3, pp.195–204. [Google Scholar] [Crossref]

3. Adesina, A. and Zinnah, M., 1992. Technology characteristics, farmers’ perception and adoption decisions: A Tobit model application in Sierra Leone. Agricultural Economics, 9, pp.297–311. [Google Scholar] [Crossref]

4. Asif, M., Rooney, L.W., Ali, R. and Riaz, M.N., 2013. Application and opportunities of pulses in food systems: A review. Riaz, pp.1168–1179. [Google Scholar] [Crossref]

5. Channal, G., Nagnur, S. and Nanjayyanamath, C., 2004. Indigenous grain storage structures. Leisa India, 6, p.10. [Google Scholar] [Crossref]

6. Chulze, S.N., 2010. Strategies to reduce mycotoxin levels in maize during storage: A review. Food Additives & Contaminants: Part A, [online] Available at: https://doi.org/10.1080/02652031003743774. [Google Scholar] [Crossref]

7. Duranti, M., 2006. Grain legume proteins and nutraceutical properties. Fitoterapia, 77(2), pp.67–82. [Google Scholar] [Crossref]

8. Ellis, R.H., Hong, T.D. and Roberts, E.H., 1992. The low-moisture-content limit to the negative logarithmic relation between seed longevity and moisture content in three subspecies of rice. Annals of Botany, 61, pp.405–408. [Google Scholar] [Crossref]

9. Hu, L., Liu, H., Yang, J., Wang, C., Wang, Y., Yang, Y. and Chen, X., 2019. Free and hidden fumonisins in raw maize and maize-based products from China. Food Additives & Contaminants: Part B, [online] Available at: https://doi.org/10.1080/19393210.2019.1587356. [Google Scholar] [Crossref]

10. Kamika, I. and Takoy, L., 2020. Aflatoxin accumulation in maize stored long-term: Risk factors and safety implications. Journal of Stored Products Research, 88, 101674. https://doi.org/10.1016/j.jspr.2020.101674. [Google Scholar] [Crossref]

11. Liu, X., Guan, X., Xing, F., Lv, C., Dai, X. and Liu, Y., 2017. Effect of water activity and temperature on the growth of Aspergillus flavus, the expression of aflatoxin biosynthetic genes and aflatoxin production in shelled peanuts. Food Control, [online] Available at: https://doi.org/10.1016/j.foodcont.2016.10.008. [Google Scholar] [Crossref]

12. Mukanga, M., Derera, J., Tongoona, P. and Laing, M.D., 2010. A survey of pre-harvest ear rot diseases of maize and associated mycotoxins in South and Central Zambia. International Journal of Food Microbiology, [online] Available at: https://doi.org/10.1016/j.ijfoodmicro.2009.10.032. [Google Scholar] [Crossref]

13. Navarro, H., Navarro, S. and Finkelman, S., 2012. Hermetic and modified atmosphere storage of shelled peanuts to prevent free fatty acid and aflatoxin formation. In: Proceedings of the Conference International Organization for Biological Control (IOBC), Working Group on Integrated Protection in Stored Products. [Google Scholar] [Crossref]

14. Rajashekar, Y., Tonsing, N., Shantibala, T. and Manjunath, J.R., 2016. 2,3-Dimethylmaleic anhydride: A plant-derived insecticidal molecule from Colocasia esculenta var. esculenta (L.) Schott. Scientific Reports, 6, p.20546. [Google Scholar] [Crossref]

15. Rathod, R.H., Chaudhari, S.R. and Patil, A.S., 2019. Ultra-high performance liquid chromatography-MS/MS (UHPLC-MS/MS) in practice: Analysis of drug and pharmaceutical formulation. Future Journal of Pharmaceutical Sciences, 5, p.6. [Google Scholar] [Crossref]

16. Shephard, G.S. and Leggott, N.L., 2019. Comparative aflatoxin accumulation in stored groundnuts and maize: Environmental storage factors. Food Control, 96, pp.153–160. https://doi.org/10.1016/j.foodcont.2018.11.019. [Google Scholar] [Crossref]

17. Sirot, V., Fremy, J.M. and Leblanc, J.C., 2013. Dietary exposure to mycotoxins and health risk assessment in the second French total diet study. Food and Chemical Toxicology, 52, pp.1–11. [Google Scholar] [Crossref]

18. Squire, R.A., 1981. Ranking animal carcinogens: A proposed regulatory approach. Science, 214, pp.877–880. [Google Scholar] [Crossref]

19. Wen, Y., Hatabayashi, H., Arai, H., Kitamoto, H.K. and Yabe, K., 2005. Function of the cypX and moxY genes in aflatoxin biosynthesis in Aspergillus parasiticus. Applied and Environmental Microbiology, 71, pp.3192–3198. [Google Scholar] [Crossref]

20. World Health Organization (WHO), 2018. Food Safety Report: Aflatoxins. Geneva: WHO. [Google Scholar] [Crossref]

21. Yabe, K. and Nakajima, H., 2004. Enzyme reactions and genes in aflatoxin biosynthesis. Applied Microbiology and Biotechnology, 64, pp.745–755. [Google Scholar] [Crossref]

22. Yabe, K., Ando, Y. and Hamasaki, T., 1991. A metabolic grid among versiconal hemiacetal acetate, versiconol acetate, versiconol and versiconal during aflatoxin biosynthesis. Journal of General Microbiology, 137, pp.2469–2475. [Google Scholar] [Crossref]

23. Yu, J., Chang, P.K., Ehrlich, K.C., Cary, J.W., Bhatnagar, D. and Cleveland, T.E., 2004. Clustered pathway genes in aflatoxin biosynthesis. Applied and Environmental Microbiology, 70, pp.1253–1262. [Google Scholar] [Crossref]

24. Yuya, A.I., Tadesse, A., Azerefegne, F. and Tefera, T., 2009. Efficacy of combining Niger seed oil with Malathion 5% dust formulation on maize against the maize weevil, Sitophilus zeamais (Coleoptera: Curculionidae). Journal of Stored Products Research, 45(1), pp.67–70. [Google Scholar] [Crossref]

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