Detection and Management of Aflatoxin Contamination in Kenyan Smallholder MaizeVincent Were1, Samuel Mutiga2, Jagger Harvey1, Vivian Hoffman3, Rebecca Nelson2, Michael Milgroom2.

1Biosciences eastern and central Africa Hub, International Livestock Research Institute, Nairobi, Kenya; 2Dept. of Plant Pathology and Plant-Microbe Biology, Cornell University, USA; 3Maryland Population Research Center, University of Maryland, USA

ResultsOf the smallholder maize samples tested to date (by Helica), 35% have tested positive for aflatoxin, 11% above the 10ppb level used by some countries as a threshold above which grains should not be consumed by humans, and 3% were above the 20ppb used as the threshold by Kenya. Note that the samples were collected in 2009, a time when aflatoxicosis was not reported. Analysis of samples from an aflatoxicosis year (2010) are in progress.

Sample collection and analysis

Conclusion: Maize samples from many areas were positive for aflatoxins, even in a year in which aflatoxicosis was not a recognized problem (May-June 2009).

Maize in Kenya: a staple crop for people and a livestock feed

Potential Management Strategies•Biological control – using atoxigenic Aspergillus which grows faster than

toxigenic Aspergillus. •Some maize have genes that help in resistance (e.g, genes that

enhance hardness of grain cover). Breeders can develop more resistant maize varieties.•Get a cheaper, easier and faster way of aflatoxin detection for

consumers (e.g., at the posho mills).•Reduce pre-harvest crop stress and insect damage, which favor fungal

infection.•Improve storage conditions.

Future directions•Completing analysis of 2009 and 2010 smallholder maize surveys.•Incorporating VICAM and Near Infrared Spectroscopy (NIRS) in aflatoxin

analysis.•Potential development of extension guide for training smallholder farmers

to properly dry, store and sort grain.•Engagement of strategic national partners to better ensure impact for

smallholder farmers in Kenya and beyond.

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Negatives Below 10 10 to 20 Above 20

Frequ

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Aflatoxin (ppb)

IntroductionAflatoxins are potent toxins and carcinogens found in the human and livestock food supply. They are produced primarily by the fungal genus Aspergillus, a pre‐ and postharvest pest. These toxins continue to be a major health problem in the developing world, where cases of acute exposure can be fatal. Aflatoxins are particularly damaging to children’s health, stunting child growth and increasing vulnerability to disease. The scope and dynamics of aflatoxin contamination of food in many parts of sub‐Saharan Africa have yet to be clearly characterized. The BecA Hub is involved in a collaborative effort to characterize the scope of the aflatoxin problem in Kenya, develop new techniques for higher throughput diagnostics and identify existing farmer practices that may help reduce aflatoxin accumulation in smallholder maize.

Expected Outputs-Build aflatoxin diagnostics capacity at the Hub, for use by African and

other partners.

-Develop novel, higher throughput diagnostics (adapt Near Infrared Spectroscopy to detect Aspergillus in maize flour).

-Characterize the aflatoxin problem in the smallholder farmer food supply.

-Limit aflatoxin accumulation and exposure through identification of proper crop management and storage conditions.

Data analysis

Grain scoring Posho mill users visually sort out moldy and damaged grains. We are investigating whether sorting reduces aflatoxin levels in maize meals, and if so, identifying which kernel characteristics can be used for effective sorting. The kernel integrity; moldiness, discolor, rot (MDR); and kernel texture was measured and correlated with aflatoxin levels. Data analysis is in progress.

Helica MycoMonitorTotal Aflatoxin Assay, a solid phase direct competitive enzyme immunoassay with adetection limit of 1 part per billion (ppb).

Aflatoxin extraction

dent flintHigh MDR score Low MDR score

Mycelium

kernels

sclerotia

Cobs Debris http://www.aspergillusflavus.org/aflavus

moldy maize grains posho mill (smallholder maize flour production)

Ugali

livestock feed milk

BecA Hub:sample analysis

Vicam aflatest(fluorometer/monoclonal antibodybasedaffinity chromatography; 0.1‐300 ppb aflatoxin measurement)

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Bungoma Eldoret Kisii Kitale Machakos Makueni Nairobi

Aflatoxin levels by area

already analyzed

Analysis in progress

Aflatoxin levels in smallholder maize

Number of samples in each Aflatoxin (ppb) bracket