- Category: Research
Establishing a regional mycotoxin analytical platform to enable reduced aflatoxin contamination of Kenyan and Tanzanian maize
Across East Africa approximately 132 million people depend on maize as a staple food. Maize crops are susceptible to accumulation of toxic fungal metabolites (mycotoxins). Given the technologies required for detection, these invisible toxins are under-recognized threats to the health of African populations and barriers to development and trade.
Food safety has become recognized as an essential component of food security. Many cereals, nuts, fruits and other important food crops are susceptible to infection by fungi that produce toxic secondary metabolites (mycotoxins). Aflatoxins (Aspergillus mycotoxins) are estimated to contaminate 25% of the global food supply - with 4.5 billion people exposed to high, unmonitored levels - primarily in developing countries1. This is likely to be exacerbated by climate change since drought-stressed crops are more susceptible to mycotoxin accumulation 2.
Mycotoxin contamination of staple foods in Africa and elsewhere is detrimental to health, trade and development. Highly carcinogenic, mycotoxins are also associated with immunosuppression, reduced nutrient absorption and stunting of infants, and are lethal in high doses 3-6. Infants are exposed in utero and after birth, since maternally consumed toxins are passed through breast milk. Further evidence suggests that mycotoxins may affect families for one or two generations beyond initial exposure.
While some African farmers recognize the potential negative health impacts of contaminated food 8, their current management options to address this are limited. Farmers often feed moldy grain to livestock; however animals are also susceptible to the toxins. Humans are nonetheless exposed since the toxins accumulate in dairy products and eggs.
In addition to the health concerns, mycotoxins can restrict African trade. For example, it was estimated that tightening European regulations would further reduce African groundnut exports by USD670 million annually 9.
In order to improve nutritional status and food safety in Kenya, Tanzania and the region, increased capacity to characterize and reduce the presence of mycotoxins in the food supply is essential. The Comprehensive Africa Agriculture Development Programme (CAADP) recently set aflatoxins as a high priority research area, establishing the Partnership for Aflatoxin Control in Africa (PACA) 10. This CAAREA project will contribute to aspects of the PACA overall aims for Africa.
How will the project contribute to research and development for Africa?
This project brings together a multi-disciplinary, multi-national team of scientists to help address the spectre of aflatoxins in eastern Africa. These scientists include Kenya and Tanzania’s national maize breeders who are leading field trials. Overall this project will underpin appropriate changes to their breeding programs to ensure reduced aflatoxin levels in Kenyan and Tanzanian maize in the future.
The project team is working to establish a regional mycotoxin analytical platform at the Biosciences eastern and central Africa - International Livestock Research Institute Hub (BecA-ILRI Hub). This shared platform will include a range of technologies including novel diagnostics well suited to the African context. These include state-of-the-art, commonly accepted aflatoxin diagnostics and sample preparation and diagnostics technologies (Romer Mills, ultra high performance liquid chromatography mass spectrometry (UHPLC), enzyme-linked immunosorbent assay (ELISA) and immunocapture-fluorometry); as well as new technologies suited to the African research and crop improvement context (near infrared spectroscopy (NIR)). While this project focuses on the application of technologies to understand targeted issues related to reducing aflatoxin contamination in these eastern African maize-based food systems; the technology platform will also provide much needed capacity to address other mycotoxin-related food security issues across a range of agricultural products. The platform is already in use by national partners conducting other mycotoxin-related research projects.
The team is assessing current aflatoxin risk so that potential mitigation strategies can be developed. Information about the pathogen and toxin prevalence across Kenya and Tanzania is being collected through nationwide on-farm surveys, filling a key gap in our current knowledge about aflatoxin prevalence and management practices. The project involves Kenyan and Tanzanian national maize breeders, affording their institutions the first opportunity to screen breeding germplasm and released varieties for aflatoxin resistance. Their field trial data will enable the team to identify maize germplasm that accumulate lower levels of aflatoxins. Aflatoxin susceptibility levels and the dynamics of environmental influence (eg, drought) will be determined through diagnostics and modeling, using pre- and post-harvest field and laboratory results. Based on project results, the national maize breeders will affect changes to their breeding programs, introducing reduced aflatoxin levels as a new trait in future released varieties.
Modeling will combine information from across the project to begin the development of real-time predictive tools to forecast potential aflatoxin outbreaks in maize. This will ultimately help policy makers to target solutions before a critical outbreak occurs in the region. Further modeling will enable the team to look beyond Kenya and Tanzania to estimate current risk and the potential impact of different mitigation strategies for the region.
Changes in the available varieties and management practices will impact more than 11 million small holder farmers who grow maize in Tanzania and Kenya. Safer maize means more reliable incomes, greater opportunities for trade and healthier food for communities.
The capacities established through this project are available for researchers to address these important food security issues for Africa.
- BecA-ILRI Hub: Jagger Harvey (Project Leader); Benoit Gnonlonfin; Samuel Mutiga; James Wainaina; Immaculate Wanjuki
- Kenya Agricultural Research Institute (KARI): James Karanja, Festus Murithi and teams
- Tanzanian Agricultural Research Institute (ARI): Arnold Mushongi and team
- Tanzania Ministry of Agriculture and Food Security: Deogratias Lwezaura and team
- Open University of Tanzania: Said Massomo
- Australia’s national science agency - The Commonwealth Scientific and Industrial Research Organisation (CSIRO): Ross Darnell; Nai Tran-Dinh; Stephen Trowell and Amalia Berna
- CSIRO/HarvestChoice: Darren Kriticos
- University of Queensland/ Queensland Alliance for Agriculture and Food Innovation (QAAFI): Mary Fletcher, Glen Fox
- The Queensland Department of Agriculture, Fisheries and Forestry (QDAFF): Yash Chauhan, Warwick Turner
- Cornell University: Rebecca Nelson and Michael Milgroom
- HarvestChoice/University of Minnesota: Phil Pardey and Jason Beddow
- University of Pretoria/HarvestChoice: Frikkie Liebenberg
Masters candidates supported within the project:
- Samuel Msuya, Open University of Tanzania; Ministry of Agriculture Training Institute
- Sammy Khakata, University of Nairobi, Kenya
Dr Jagger Harvey - Project Leader and Research Scientist, BecA-ILRI Hub,
Related CSIRO projects:
- Stephen Trowell and Amalia Berna (electronic nose; CSIRO)
- Yash Chauhan (APSIM modeling; Queensland Department of Employment, Economic Development and Innovation - QDEEDI)
- FAO website
- Magan et al. 2011, Plant Pathol. 60: 150-163.
- Gong et al. 2002, Brit. Med. J. 325: 20-21.
- Rahimi et al. 2010, Food Chem. Toxicol. 48: 129-131.
- Williams et al. 2004, J. Americ. of Clin. Nutrit. 80: 1106-1122.
- Henry et al. 1999. Sci. 286: 2453-2454.
- Bygren et al. 2001, Acta Biotheor. 49: 53–59.
- Harvey, Hoffman et al., manuscript in preparation
- Otzuki et al. 2001, Eur. Review of Agricultural Econ. 28: 263-283.
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