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Reducing human exposure to aflatoxins in poor countries: Towards new technologies and practices


ILRI graduate fellow Taishi Kayano, from Rakuno Gakuen University, collects milk samples from a Kenya dairy farmer as part of a scoping survey of aflatoxins in the feed-dairy chain in Kenya (photo credit: ILRI/Taishi Kayano).

A new paper describes and assesses the strength of a theory of change for how adoption of farm-level technologies and practices for aflatoxin mitigation can help reduce aflatoxin exposure among consumers.

‘Aflatoxins, naturally occurring fungal toxins that contaminate maize and groundnuts and other crops, pose both acute and chronic risks to human health. Aflatoxins are odourless and colourless and impossible to detect accurately without appropriate testing technologies. Both humans and animals are affected, and there is an additional risk of aflatoxin transmission through animal-source foods, especially milk, from animals fed contaminated feed.

‘Consumption of very high levels of aflatoxins can result in acute illness and death. Chronic exposure, which causes the greater human health burden, is a problem in low-income populations in the tropics that consume relatively large quantities of staple crops prone to aflatoxin contamination. The best-documented health impact of chronic exposure to aflatoxins is liver cancer; up to 172,000 cases per year are attributable to aflatoxin exposure. Other health effects, such as immune suppression and child stunting, have also been associated with aflatoxin exposure.

‘While the health impacts of aflatoxin in humans have been widely studied, the correlations between dietary consumption, serum aflatoxin levels, and morbidity and mortality outcomes have not been clearly described or documented. More evidence on these relationships is needed in order to assess the disease burden from aflatoxin exposure relative to other public health problems, and to estimate the cost-effectiveness of alternative mitigation options in developing-country contexts.

‘In addition to the health consequences, the presence of aflatoxins can reduce agricultural productivity and limit the growth of commercial markets and trade. In developed countries, strict standards are enforced to minimize aflatoxins on crops consumed by humans or animals. These standards have implications for market access and exports from Africa and other regions where aflatoxin contamination is common and where standards are not currently in place or enforced. Where aflatoxins are widespread and the costs of mitigation and testing are high, meeting standards remains challenging. Quality differentiation based on either market rewards or public standards is still unusual in most developing countries. Innovative approaches that combine technological and institutional change with increased education and consumer awareness are likely to be required to address this challenge in the near term. Within agriculture, research has focused on developing farm-level technologies and practices that mitigate aflatoxins at their source, in farmers’ fields.

‘Pre- and post-harvest technologies have been shown to be effective in terms of inhibiting aflatoxin contamination, in many cases to within international standards. Application of proven and existing “good agricultural practices” in production and post-harvest (for example, drying and storage) can also reduce aflatoxin contamination. However, studies have found that knowledge and awareness about aflatoxins is generally low, as is use of risk-reducing practices, among smallholder farmers and other stakeholders, particularly along the maize, groundnut, and milk value chains.

‘More work is needed on developing, adapting, and promoting risk-mitigating technologies and strategies and on understanding the incentives for and barriers to their widespread adoption. Because of the complex, multifaceted nature of the aflatoxin challenge, it is important to look at specific solutions such as agricultural technologies in the broader context of how they are expected to contribute not just to reducing on-farm aflatoxin contamination but also to achievement of the ultimate goals of food and nutrition security, economic development, and public health. To date, little attention has been paid to how adoption of these technologies would influence health outcomes. A win-win situation is often assumed; however, the link between agricultural technology adoption and public health outcomes is complex, especially where markets are important for producers and consumers, and the risk of unintended negative consequences may be significant.

‘Developing a theory of change that articulates how the adoption of these technologies is expected to contribute to better health outcomes is a useful way to make explicit and examine causal models, build a shared understanding of the potential for impact, and plan and monitor progress. While typically used in the context of specific projects or interventions, a theory of change is also useful in research for development, to synthesize existing information and experience regarding how the pathways work in specific contexts and identify gaps and priority areas for future research or related activities. . . .’

Read the whole theory of change analysis—IFPRI Discussion Paper 01452, July 2015: The potential of farm-level technologies and practices to contribute to reducing consumer exposure to aflatoxins: A theory of change analysis, by Nancy Johnson, of the CGIAR Research Program on Agriculture for Nutrition and Health (A4NH) at the International Food Policy Research Institute (IFPRI); Christine Atherstone, ILRI consultant; and Delia Grace, leader of the agriculture-associated diseases flagship of A4NH and of ILRI’s Food Safety and Zoonosis program.

More CGIAR information on aflatoxins

View an ILRI infographic: Aflatoxin: A fungal toxin affecting the food chain

View an ILRI poster: Levels of aflatoxins in the Kenyan dairy value chain: How can we assess the economic impact?, Oct 2013

Read previous articles about this event:
Aflatoxins in Kenya’s food chain: Overview of what researchers are doing to combat the threat to public health, 6 May 2014
‘Bio-control’=effective control of aflatoxins poisoning Kenya’s staple food crops, 13 Feb 2014
Dairy feed project to reduce aflatoxin contamination in Kenya’s milk, 11 Feb 2014
Australia-funded research fights aflatoxin contamination in East African foods, 6 Feb 2014

Read an ILRI News Blog article introducing a 6-minute film interview of five panelists at the media roundtable on aflatoxins in Kenya: Reducing aflatoxins in Kenya’s food chains: Filmed highlights from an ILRI media briefing, 19 Dec 2013

Read an ILRI News blog article introducing a 6-minute ILRI film interview of John McDermott (IFPRI) and Delia Grace (ILRI), who lead research on aflatoxins for A4NH: Fighting aflatoxins: CGIAR scientists Delia Grace and John McDermott describe the disease threats and options for better control, 8 Nov 2013

Read more about the 19 IFPRI aflatoxin briefs released in Nov 2013: http://www.ifpri.org/publication/aflatoxins-finding-solutions-improved-food-safety

Read the whole publication: Aflatoxins: Finding solutions for improved food safety, edited by Laurian Unnevehr and Delia Grace

Download Table of Contents and Introduction
1. Tackling Aflatoxins: An Overview of Challenges and Solutions by Laurian Unnevehr and Delia Grace
2. Aflatoxicosis: Evidence from Kenya by Abigael Obura
3. Aflatoxin Exposure and Chronic Human Diseases: Estimates of Burden of Disease by Felicia Wu
4. Child Stunting and Aflatoxins by Jef L Leroy
5. Animals and Aflatoxins by Delia Grace
6. Managing Mycotoxin Risks in the Food Industry: The Global Food Security Link by David Crean
7. Farmer Perceptions of Aflatoxins: Implications for Intervention in Kenya by Sophie Walker and Bryn Davies
8. Market-led Aflatoxin Interventions: Smallholder Groundnut Value Chains in Malawi by Andrew Emmott
9. Aflatoxin Management in the World Food Programme through P4P Local Procurement by Stéphane Méaux, Eleni Pantiora and Sheryl Schneider
10. Reducing Aflatoxins in Africa’s Crops: Experiences from the Aflacontrol Project by Clare Narrod
11. Cost-Effectiveness of Interventions to Reduce Aflatoxin Risk by Felicia Wu
12. Trade Impacts of Aflatoxin Standards by Devesh Roy
13. Codex Standards: A Global Tool for Aflatoxin Management by Renata Clarke and Vittorio Fattori
14. The Role of Risk Assessment in Guiding Aflatoxin Policy by Delia Grace and Laurian Unnevehr
15. Mobilizing Political Support: Partnership for Aflatoxin Control in Africa by Amare Ayalew, Wezi Chunga and Winta Sintayehu
16. Biological Controls for Aflatoxin Reduction by Ranajit Bandyopadhyay and Peter J Cotty
17. Managing Aflatoxin Contamination of Maize: Developing Host Resistance by George Mahuku, Marilyn L Warburton, Dan Makumbi and Felix San Vicente
18. Reducing Aflatoxins in Groundnuts through Integrated Management and Biocontrol by Farid Waliyar, Moses Osiru, Hari Kishan Sudini and Samuel Njoroge
19. Improving Diagnostics for Aflatoxin Detection by Jagger Harvey, Benoit Gnonlonfin, Mary Fletcher, Glen Fox, Stephen Trowell, Amalia Berna, Rebecca Nelson and Ross Darnell

3 thoughts on “Reducing human exposure to aflatoxins in poor countries: Towards new technologies and practices

  1. Aflatoxins and aflatoxins contamination is a serious problem in Ghana especially northern Ghana where large quantities of groundnuts, maize and fresh milk are consumed by the rural-poor.

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