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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Pest Management and Biocontrol Research » Research » Publications at this Location » Publication #331595
Research Project: Improved Environmental and Crop Safety by Modification of the Aspergillus flavus Population Structure

Location: Pest Management and Biocontrol Research

Title: Aflatoxin contamination of groundnut and maize in Zambia: observed and potential concentrations

Author
item KACHAPULULA, PAUL - UNIVERSITY OF ARIZONA
item AKELLO, JULIET - INTERNATIONAL INSTITUTE OF TROPICAL AGRICULTURE (IITA)
item BANDYOPADHYAY, RANAJIT - INTERNATIONAL INSTITUTE OF TROPICAL AGRICULTURE (IITA)
item COTTY, PETER

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2017
Publication Date: 5/16/2017
Citation: Kachapulula, P.W., Akello, J., Bandyopadhyay, R., Cotty, P.J. 2017. Aflatoxin contamination of groundnut and maize in Zambia: observed and potential concentrations. Journal of Applied Microbiology. 122:1471-1482.

Interpretive Summary: Aflatoxins are toxic fungal metabolites that can inhibit human development, cause cancer, and even induce death. Occurrence of these toxins greatly reduces the markets to which crops can be sold and the health of consuming populations. The fungi named Aspergillus flavus and A. parasiticus are the primary cause of aflatoxin contamination of several crops. In order to understand the epidemiology of contamination and the risk these fungi pose to human health and trade, populations of A. flavus and A. parasiticus were examined in the climates where crops are grown in Zambia. Agroecology was found to be an important influence of crop contamination although toxic fungi were found countrywide. The current work suggests that the target agroecology must be taken into consideration when designing procedures to manage aflatoxins. This might be particularly impactful in developing biocontrols based on atoxigenics strains of A. flavus for Zambia.

Technical Abstract: Maize and groundnut, important staples in Zambia, are susceptible to aflatoxin-producing fungi. Aflatoxins are potent human carcinogens also associated with stunting and immunosuppression. Although health and economic burdens of aflatoxins are well known, patterns of contamination in maize and groundnuts across Zambian agroecologies are largely unexplored. Aflatoxin concentrations were determined for 334 maize and groundnut samples from 27 districts using lateral-flow immunochromatography. Fifteen percent of crops purchased in markets contained aflatoxin concentrations above the CODEX limit for human consumption (10 ppb). Crop proportions unsafe for human consumption differed significantly (p<0.001) among agroecologies with the highest proportion in region I (38%) and lowest in region III (8%). Total aflatoxin concentrations in groundnut (39 ppb) significantly exceeded (P = 0.032) those found in maize (16 ppb). Simulated poor storage (31°C, 100% RH, 1 week) increased aflatoxin from 3 ppb to 4,418 ppb (t34 = 8.86, P < 0.0001) in maize and from 3 ppb to 100,302 ppb in groundnuts (t39 = 12.19, P < 0.0001). Incidences of A. flavus L­ morphotype were negatively correlated with aflatoxin increases in groundnut (R2 = 0.55, P < 0.001) but not maize. The results suggest fungal community structure influences both pre and post-harvest contamination and Zambia would benefit from aflatoxin management.