ILRI sponsors special journal issue on aflatoxins in eastern Africa

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.

Editorial
Aflatoxins in East Africa: The importance of getting the full picture (http://hdl.handle.net/10568/76526)

Understanding the health impacts

• Assessing the impact of aflatoxin consumption on animal health and productivity (http://hdl.handle.net/10568/76497)
• Aflatoxin exposure among young children in urban low-income areas of Nairobi and association with child growth (http://hdl.handle.net/10568/76498)

Extent and location of the problem

• Aflatoxin B1 occurrence in millet, sorghum and maize from four agro-ecological zones in Kenya (http://hdl.handle.net/10568/76499)
• Prevalence of aflatoxin in feeds and cow milk from five counties in Kenya (http://hdl.handle.net/10568/76501)
• Survey of informal milk retailers in Nairobi, Kenya and prevalence of aflatoxin M1 in marketed milk (http://hdl.handle.net/10568/76502)
• 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 (http://hdl.handle.net/10568/76503)
• 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 (http://hdl.handle.net/10568/76495)
• 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

 

New ILRI study finds high levels of aflatoxin in milk and dairy feeds in Greater Addis Ababa milk shed

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.

Citation
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 http://hdl.handle.net/10568/67116

 

Uganda pig feed trials show benefits of local feed solutions

CGIAR Research Program on Livestock and Fish

Research assistants chopping jackfruit (left) and weighing a feed trial pig (right) at Kamuzinda Farm, Uganda (photo credit: ILRI/Natalie Carter).

Pig production in Uganda is on the rise. The number of pigs in the country stood at 3.2 million in 2011 (based on a livestock census) from about 200,000 thirty years ago. A rise in the country’s population and incomes has triggered an upsurge in pork consumption. The per capita pork consumption of Uganda was 3.4 kg per person per annum in 2011, the highest in the East Africa region. Most of the pork consumed in the country is supplied by smallholder producers in over 1 million households, with women playing a central role in pig farming.

These figures, however, disguise challenges in the sector including diseases and parasites, unreliable markets, inadequate extension services and most importantly, poor quality and unavailability of pig feeds.

A 2013 value chain assessment conducted by the International…

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ILRI project surveys aflatoxin risk in the feed-dairy chain in Kenya

ILRI graduate fellow Taishi Kayano collects milk samples from a Kenyan dairy farm as part of a qualitative survey on aflatoxins in the dairy chain in Kenya. (photo credit: ILRI/Taishi Kayano).

In January 2013, an international, multidisciplinary team of five upcoming researchers undertook a scoping survey of aflatoxins in the feed-dairy chain in Kenya as part of activities of the project, “Measuring and mitigating the risk of mycotoxins in maize and dairy products for poor consumers in Kenya” (MyDairy project).

The team comprised Kenyan PhD students Anima Sirma and Daniel Senerwa, American intern Calvin Pohl, Japanese veterinary student Taishi Kayano and Kenyan postdoctoral scientist Teresa Kiama.

They visited nine districts and 27 villages in rural Kenya where they led participatory rapid appraisals on dairying and aflatoxins and held focus group discussions with women dairy farmers.

In addition, all the communities visited were given information and training on safe handling and storage of milk and animal feed.

The qualitative part of the survey collected data on the type of feeds, milk yield and the storage period for milk and feed, among other variables.

Samples of milk and feed were also collected for laboratory analysis to investigate the association between the condition of cattle and the prevalence of aflatoxin in milk.

The results of the qualitative survey are being analyzed but preliminary findings show that the surveyed farmers use a variety of feeding practices for their dairy cattle and most of the milk is marketed in the informal sector as raw, unprocessed milk.

Recalling his field research experience as an ILRI graduate fellow, Kayano had this to say:

“I visited farmers with livestock officers or chiefs in the districts. Without their help, I wouldn’t have been able to get meet the local farmers and collect the milk and feed samples.

“They also helped to identify the precise locations of the dairy farms; this was very useful as there are no detailed maps of dairy farms.

“The livestock officers also translated our questionnaires from English to Kiswahili which was a key step in acquiring the data needed for the study.

“An internship at ILRI is a really good opportunity for students who would like to work on a short-term basis in an international research institution and to experience doing research in a developing country context.”

Read more about the MyDairy project