Maize. Mozambique, Tete province, Pacassa village (photo credit: ILRI/Mann).

In sub-Saharan Africa, contamination of dairy feed with mycotoxins has been frequently reported. Mycotoxins pose a threat to animal health and productivity and are a hazard to human health as some mycotoxins and their metabolites are excreted in milk, such as aflatoxin M1.

A new review paper published in the journal Toxins (April 2020) describes the major mycotoxins, their occurrence and their impact in dairy cattle diets in sub-Saharan Africa, highlighting the problems related to animal health, productivity and food safety and the latest post-harvest mitigation strategies to prevent and reduce contamination of dairy feed with mycotoxins.

Kemboi, D.C., Antonissen, G., Ochieng, P.E., Croubels, S., Okoth, S., Kang’ethe, E.K., Faas, J., Lindahl, J.F. and Gathumbi, J.K. 2020. A review of the impact of mycotoxins on dairy cattle health: Challenges for food safety and dairy production in sub-Saharan Africa. Toxins 12(4): 222.

Photo credit: Maize crop, Pacassa village, Tete province, Mozambique (ILRI/Mann)

Women threshing sorghum in Angonia province, Mozambique (photo credit: ILRI/Stevie Mann).

There are too many issues with using lactic acid bacteria for aflatoxin binding for the practice to be safely promoted, according to a newly published review. The review adds that using aflatoxin binders in human food might even worsen food safety in the longer term.

“Use of binding agents in foods contradicts all the existing principles and regulations set to ensure food safety. If such a method is promoted, the efforts to combat the aflatoxin problem at farm level and throughout the value chain, to eliminate and reduce the contaminants, could be compromised,” the study says.

Aflatoxins continue to be a food safety problem globally, especially in developing regions. A significant amount of effort and resources have been invested to control aflatoxins. However, these efforts have not substantially decreased the prevalence nor the dietary exposure to aflatoxins in developing countries. 

One approach to aflatoxin control is the use of binding agents in foods, and lactic acid bacteria have been studied extensively for this purpose. However, when assessing the results comprehensively and reviewing the practicality and ethics of use, risks are evident and concerns arise. 

The study notes that aflatoxin binding research has approached the issue from a one-component ‘silver bullet’ solution instead of focusing on a comprehensive approach to aflatoxin control that considers good agricultural practices at the farm level and good manufacturing practices during production. 

Promoting increased diversity of diets, particularly of staple crops, may contribute towards reduced exposure to aflatoxins. Additionally, the role of food safety authorities needs to be strengthened to safeguard food quality in both formal and informal markets.


Ahlberg, S., Randolph, D., Okoth, S. and Lindahl, J. 2019. Aflatoxin binders in foods for human consumption—Can this be promoted safely and ethically? Toxins 11(7): 410.

Photo credit: Women threshing sorghum in Angonia Province, Mozambique (ILRI/Stevie Mann)

A4NH 2017 annual report cover

The CGIAR Research Program on Agriculture for Nutrition and Health (A4NH) has published its 2017 annual report which highlights the program’s accomplishments and activities during the first year of its second phase.

Detailed in the report are research, events and results from across A4NH’s five research flagships and four focus countries, including:

  • in-depth analyses of food systems in Bangladesh, Ethiopia, Nigeria and Vietnam, with a recently released report on findings in Ethiopia;
  • details on the release of 29 new biofortified crop varieties, extending reach to 3.6 million farming households;
  • the first licence for Aflasafe to be granted to a private company in Africa, for production, sale, and distribution in the Gambia and Senegal to protect crops from aflatoxin;
  • a special issue of the journal Global Food Security dedicated to stories of change, an innovative initiative building a resource base of experiential knowledge that explores drivers of change in improving nutrition;
  • research into how rice intensification in Africa can be achieved without increasing the risk of malaria; and
  • efforts on incorporating equity into A4NH’s research agenda.

Download the annual report or read an interactive online version.

Panel discussion at the 'Growing with dairy' meeting held at ILRI Nairobi, 9 March 2018

Erastus Kang’ethe (standing) facilitates a panel discussion at the ‘Growing with Dairy’ meeting. The panel members (left to right) are Johanna Lindahl from ILRI, Humphrey Mbugua from the Association of Kenya Feed Manufacturers and Margaret Aleke from the Kenya Bureau of Standards (photo credit: ILRI/Emmanuel Muunda).

Representatives from the dairy sector in Kenya met at the Nairobi campus of the International Livestock Research Institute (ILRI) in March 2018 for a one-day meeting organized to present the research findings and plans of two dairy projects that ILRI is undertaking in collaboration with other partners: Measuring and mitigating the risk of mycotoxins in maize and dairy products for poor consumers in Kenya (MyDairy) and MoreMilk: making the most of milk (MoreMilk).

The meeting, dubbed Growing with Dairy, brought together 33 participants representing different stakeholder groups in Kenya’s dairy sector including industry, government, consumers, academia and development organizations.

Presentations by the principal investigators of the MyDairy and MoreMilk projects discussed various activities and interventions aimed at improving the dairy sector in Kenya and boosting the health and economic benefits that Kenyans derive from the sector.

The meeting also provided an opportunity to disseminate research findings, receive feedback on ongoing and planned activities, and align project objectives with the needs of public and private actors in the dairy sector in Kenya.

The MyDairy project was funded by the Ministry of Foreign Affairs, Finland and implemented between 2012 and 2018 in two phases: an initial four-year phase followed by a second phase of 1.5 years. The project aimed at mitigating the risks of aflatoxins in the dairy value chain in Kenya.

The MoreMilk project is a five-year initiative (2016–2021) funded by the Bill & Melinda Gates Foundation and the United Kingdom government that works to upgrade milk hygiene and quality standards in the informal dairy value chain and maximize economic, health and nutrition benefits, especially for the poorest communities in Nairobi.

Download the Growing with Dairy meeting report

Aflatoxin-contaminated groundnut kernels

Aflatoxin-contaminated groundnut kernels from Mozambique (photo credit: IITA).

A special issue of the African Journal of Food, Agriculture, Nutrition and Development (AJFAND) published in July 2016 and sponsored by the International Livestock Research Institute (ILRI) features 12 peer-reviewed scientific articles on aflatoxins in eastern Africa.

The three broad objectives of the special issue are to understand the health consequences of aflatoxins, characterize the extent of the problem and identify key elements to underpin the way forward to mitigation.

The papers, listed below, are all open access and the PDFs are freely available for download at the AJFAND website.

Aflatoxins in East Africa: The importance of getting the full picture (

Understanding the health impacts

Extent and location of the problem

  • Aflatoxin B1 occurrence in millet, sorghum and maize from four agro-ecological zones in Kenya (
  • Prevalence of aflatoxin in feeds and cow milk from five counties in Kenya (
  • Survey of informal milk retailers in Nairobi, Kenya and prevalence of aflatoxin M1 in marketed milk (
  • Assessment of pre-harvest aflatoxin and fumonisin contamination of maize in Babati District, Tanzania
  • Aflatoxin and fumonisin contamination of marketed maize and maize bran and maize used as animal feed in northern Tanzania
  • Mapping aflatoxin risk from milk consumption using biophysical and socio-economic data: A case study of Kenya (
  • Examining environmental drivers of spatial variability in aflatoxin accumulation in Kenyan maize: Potential utility in risk prediction models

Finding the way forward to mitigation

  • Farmer perception of moulds and mycotoxins within the Kenya dairy value chain: A gendered analysis (
  • A review of agricultural aflatoxin management strategies and emerging innovations in sub-Saharan Africa
  • Potential of lactic acid fermentation in reducing aflatoxin B1 in Tanzania maize-based gruel

ILRI news


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…

View original post 1,188 more words

ILRI aflatoxin infographic

Aflatoxins are highly toxic fungal by-products produced by certain strains of Aspergillus fungi in more than 40 susceptible crops including maize and groundnuts. Aflatoxins can be separated into aflatoxins B1, B2, G1 and G2.

When ingested, aflatoxin B1 is metabolized to aflatoxin M1 which is secreted into milk. Aflatoxin B1 is particularly important because it has been found in most foods and animal feeds and is highly carcinogenic.

Aflatoxins cause around 90,000 cases of liver cancer each year and are strongly associated with stunting and immune suppression in children. Aflatoxins in contaminated animal feed can lead to reduced animal productivity. They can end up in products like milk, meat and eggs, thus presenting a health risk to humans, with children being particularly susceptible.

In Ethiopia, previous studies have investigated aflatoxin contamination in staple cereals, red chili pepper and ground peas. Now, a new research study published in the journal Food Control (6 July 2015) has, for the first time, documented aflatoxin contamination in milk and dairy feeds in Ethiopia and the results show that milk and dairy feeds in the Greater Addis Ababa milk shed are highly contaminated with aflatoxins.

The cross-sectional study by scientists from the International Livestock Research Institute (ILRI) was carried out in the Greater Addis Ababa milk shed between September 2014 and February 2015 in order to detect and quantify the levels of aflatoxin M1 in samples of raw cow’s milk and aflatoxin B1 in samples of dairy feed.

The Greater Addis Ababa milk shed was selected because it is a rapidly intensifying system where aflatoxins are likely to be an increasing problem. A value chain approach was used, whereby production, processing and marketing of dairy feeds and milk were examined, as well as milk sold to consumers in Addis Ababa.

A total of 110 milk samples (100 from dairy farmers and 10 from milk traders) and 156 dairy feed samples (114 from farmers and 42 from feed producers, processors and traders) were collected and analysed by enzyme-linked immunosorbent assay (ELISA).

The study analysed all the commonly used dairy feeds such as mixed concentrate feed, brewery by-products, maize grain, pea hulls and silage. The most common ingredients in concentrate feeds were wheat bran, noug cake, pea hulls and maize grain.

All the milk samples were found to be contaminated with aflatoxin M1. Over 90% of the milk samples contained aflatoxin M1 levels that exceeded the European Union limit of 0.05 micrograms per litre. Out of a total of 110 milk samples, only nine contained aflatoxin M1 levels below 0.05 micrograms per litre.

Similarly, all the feed samples were contaminated with aflatoxin B1, with levels ranging from 7 to 419 micrograms per kilogram. Along the value chain from farmers to feed manufacturers and traders, the levels of aflatoxin contamination were fairly similar.

Out of a total of 156 dairy feed samples, only 16 contained aflatoxin B1 at a level less than or equal to 10 micrograms per kilogram. At the same time, 41 feed samples contained aflatoxin B1 at levels exceeding 100 micrograms per kilogram.

There was a significant association between aflatoxin B1 contamination in concentrate feeds and the presence of noug cake in the feed.

Noug (Guizotia abyssinica or Niger seed) is an oilseed crop that is indigenous to Ethiopia. Noug seed is pressed to produce noug oil while the remaining noug cake is sold as animal feed to feed processors and dairy farmers. Noug cake is becoming increasingly popular among dairy farmers in Ethiopia because its high nutrient content increases animal productivity.

Noug cakes were found to be highly contaminated with aflatoxin B1 (290–397 micrograms per kilogram) while the other feed components (wheat bran, maize grain and Brewer’s dry yeast) had relatively low levels of aflatoxin.

For this reason, the authors of the study recommend that further research on aflatoxin risk mitigation should focus on noug cake so as to effectively reduce the risk of aflatoxin contamination in peri-urban and urban dairy value chains in Ethiopia. Risk assessment of aflatoxins in noug seed and its by-products in other food chains should also be carried out.

In addition, there is an overall need to increase awareness of aflatoxins and to support risk mitigation practices along the entire dairy value chain.

“Policymakers and development organization need to support the dissemination of information about good agricultural and storage practices and other simple risk-reduction measures,” the authors conclude.

Gizachew D, Szonyi B, Tegegne A, Hanson J and Grace D. Aflatoxin contamination of milk and dairy feeds in the Greater Addis Ababa milk shed, Ethiopia. Food Control 59(2016): 773-779.

You may download a 4-page brief of the research article at

Working in the maize field in Malawi

Working in the maize field in Malawi (photo credit: ILRI/Stevie Mann).

The CGIAR Consortium, made up of 15 research centres, carries out agricultural research to contribute to the global effort to find solutions to the problems of poverty, hunger, food and nutrition insecurity, and environmental degradation.

Although there is still some disconnection between agriculture, health and nutrition, it is recognized that agriculture does indeed have important effects on human health. Aflatoxins, for example, pose significant health risks in tropical and subtropical regions.

Aflatoxins are highly toxic fungal by-products produced by certain strains of Aspergillus flavus in more than 40 susceptible crops including maize and groundnuts. Aflatoxins cause around 90,000 cases of liver cancer each year and are strongly associated with stunting and immune suppression in children. Aflatoxins in contaminated animal feed not only result in reduced animal productivity, but the toxins can end up in products like milk, meat and eggs, thus presenting a health risk to humans.

A new research paper published in the journal Food Security (20 May 2015) discusses how agricultural research by CGIAR can reduce the health risks from aflatoxin exposure for poor consumers while increasing the opportunities for poor farmers.

The paper, International agricultural research to reduce food risks: case studies on aflatoxins, begins with an overview of the evolution of CGIAR research on food safety and aflatoxins.

It then presents case studies to show how risk-based and market-based approaches as well as crop genetic improvement and biological control can help provide justification for and add value to future CGIAR research on aflatoxins.

In conclusion, the authors present five priority research activities:

  1. Generating evidence on the human and animal health impacts of aflatoxins
  2. Understanding the potential of improved technologies and good agricultural practices to reduce aflatoxin exposure in farm households and communities
  3. Assessing the costs and benefits of proposed strategies on aflatoxin reduction as well as other goals such as income and food security
  4. Assessing how costs and benefits are distributed across men and women in households and across different types of households in communities
  5. Understanding factors that facilitate and constrain adoption of aflatoxin control strategies would also be assessed, with particular emphasis on gender issues, incentives and on the role of health information and communication.

The paper was written by scientists from the following CGIAR centres: the International Livestock Research Institute (ILRI), the International Institute of Tropical Agriculture (IITA), the International Food Policy Research Institute (IFPRI) and the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).

Grace D, Mahuku G, Hoffmann V, Atherstone C, Upadhyaya HD and Bandyopadhyay R. 2015. International agricultural research to reduce food risks: case studies on aflatoxins. Food Security 7(3): 569-582.

Mozambique, Tete province, Pacassa village

Harvested maize in Tete Province, Mozambique (photo credit: ILRI/Stevie Mann).


As part of celebrations in Nairobi last week to mark Europe Day 2015, the Finland-funded FoodAfrica program took part in an exhibition at the residence of the European Union Delegation to the Republic of Kenya where several project outputs were showcased.

FoodAfrica is a research and development program aimed at providing new knowledge and tools for researchers, decision-makers and farmers towards improved local food security. The program works in Benin, Cameroon, Ghana, Kenya, Senegal and Uganda.

Sara Ahlberg, a Finnish associate professional officer and PhD student attached to the International Livestock Research Institute in Nairobi, presented a poster that highlighted research approaches by the FoodAfrica program to reduce the risk of mycotoxins in the feed-dairy value chain in Kenya, namely,

  • Integrated risk and economic assessment of the Kenyan feed-dairy chain
  • Investigation of technologies and strategies to reduce mycotoxin risk in the feed-dairy chain
  • Impact assessment of a package of post-harvest strategies for reducing aflatoxins in maize

View the poster, FoodAfrica – Reducing risk of mycotoxins

Aflatoxin-contaminated groundnut kernels

Aflatoxin-contaminated groundnut kernels from Mozambique (photo credit: IITA).

Among the many research projects carried out by the Food Safety and Zoonoses program of the International Livestock Research Institute (ILRI) is one that aims to reduce the risk of mycotoxins in the feed-dairy value chain in Kenya so as to improve food safety and safeguard the health of consumers of maize and dairy products.

The project is developing cost-effective and incentive-based mycotoxin control strategies and solutions for use by poor farmers and other actors within the feed-dairy chain.

Mycotoxins are poisonous metabolites produced by various species of moulds. Aflatoxins are cancer-causing mycotoxins produced by the mould Aspergillus flavus.

Aspergillus can grow in a wide range of foods and feed and thrives under favourable growth conditions of high temperature and moisture content.

The main activities of the project are:

  • risk assessment of the Kenyan feed-dairy chain to identify the best control options and provide risk managers with information for decision-making
  • assessment of the economic costs of aflatoxins in Kenya’s dairy value chain and examination of the cost effectiveness of mitigation strategies
  • investigation of technologies and strategies to reduce mycotoxins risk in the feed-dairy chain
  • impact assessment of a package of post-harvest strategies for reducing aflatoxins in maize
  • dissemination of evidence and building capacity of local researchers and postgraduate students through participation in designing surveys, fieldwork and data analysis

The project also applies participatory methods to develop and test strategies to mitigate the risk of mycotoxins in the feed-dairy chain.

These participatory methods engage farmers in action research on their fields so they can learn and adopt new technologies and disseminate the knowledge to other farmers.

The project is hosted in the aflatoxin research platform of the Biosciences eastern and central Africa (BecA) Hub at ILRI’s headquarters in Nairobi. The platform was set up to provide African scientists and their research partners access to state-of-the-art facilities for nutritional and aflatoxin analysis.

The February 2015 issue of the Aflatoxin Partnership Newsletter, published by the Partnership for Aflatoxin Control in Africa, highlights the aflatoxin platform in an article by Jagger Harvey, a senior scientist at the BecA-ILRI Hub.

Since its establishment in 2011, the platform has hosted work of more than 60 researchers from seven African countries, Australia, Europe and North America,” writes Harvey.

“Collectively, the community around the laboratory has made initial assessments of aflatoxin contamination in a number of countries, conducted the first inoculated field trials in the region to identify maize varieties less susceptible to aflatoxin accumulation, developed models estimating aflatoxin risk at harvest and produced a range of other important findings and tools which are beginning to reach end users to help ensure safer food and feed for Africa”.