Direct market costs of aflatoxins in Kenyan dairy value chain

Introduction Mycotoxin producing fungi contaminate feeds pre- or post harvest and produce aflatoxins B1, B2, G1 and G2. Aflatoxin B1 is a class 1 human carcinogen and is converted to aflatoxin M1 by cows and secreted in milk. Aflatoxin M1 is a class 2B (possible) carcinogen and is associated with stunting in children. Aflatoxin B1 in feeds causes a decrease in milk production, reduced feed conversion efficiency and reduced fertility. A cross-sectional study to assess the economic costs of aflatoxins was done in five counties in Kenya. Methods A map of the five agro-ecological zones of Kenya was used to select the study sites: Kisii and Bungoma (temperate), Tharaka-Nithi (humid), Kwale (sub-humid), and Isiolo(semi-arid). One sublocation was randomly selected from each county. Multistage cluster sampling was done with sub-locations, then villages, then dairy farmers (Dohoo et al., 2012). Milk samples were collected from the dairy farmers. Feed samples were collected from the dairy farmers, feed traders and feed manufacturers. Aflatoxin B1 and M1 quantification in dairy feeds and milk was done using a competitive ELISA. Possible economic costs of aflatoxins were estimated using annual quantities/market prices of feeds and milk having aflatoxin B1 or M1 respectively above the WHO/FAO standards. Findings and interpretations Sixty two of 101 (61.4%) dairy feed samples from feed manufacturers had aflatoxin B1 levels above the FAO/WHO/Kenya limit of 5 ppb. If this Kenyan legislation would be enforced, the possible economic cost per year for dairy feed manufacturers would be 22.2 billion US$. Seventeen of 118 (14.4$. Of the 283 milk samples from the five counties, 10.3% had aflatoxin B1 levels above WHO/FAO limit of 50 ppt which would cost dairy farmers 113.4 million US $ per year, if legislation was enforced. Education of farmers, feed manufacturers and traders on good agricultural and feed storage practices could reduce the level of contamination and multiplication of aflatoxin producing fungi and increase profits for the dairy farmers

How qualitative studies and gender analysis can add value to the assessment of dietary exposure to aflatoxins in Kenya

In tropical countries, maize, groundnuts, sorghum and milk are often contaminated by mycotoxins, which are toxic substances produced by fungi. High levels of exposure are fatal and lower levels can cause liver cancer in people and growth depression in livestock. Mycotoxicosis constitutes a classic ‘one health’ problem that affects the health of humans and livestock. Kenya has had some of the world’s severest outbreaks of mycotoxicosis and surveys typically show a high level of contamination of staple foods. Howe­ver, much less is known about the potential health risks of contaminated milk. This paper documents the results of a qualitative study conducted in Kenya on risk of exposure to mycotoxins in the dairy value chain in which the knowledge, attitude and practices of mycotoxin management by men and women were compared. A risk map was developed based on previous occurrence of aflatoxicosis and other factors such as farming systems and dairy cattle density. From this, three categories were identi­fied: high risk with and without historical outbreaks and low risk with historical outbreaks. Three districts were randomly selected per category and from each district, three villages. Two sex-disaggregated focus group discussions (FGDs) were conducted per village giving a total of 54 FGDs. Results of the study were analysed inductively, whereby trends and patterns identified were categorized to support or challenge existing theories. We found low awareness of mycotoxicosis or carcinoge­nic effects of mycotoxins, but high awareness that eating mouldy food is harmful. Men in high risk areas appeared to have more knowledge of mould types than women from the same locations. In contrast, women practiced more caution towards feeding cattle spoilt maize. More preventive mea­sures against fungal contamination in storage than on farm were practiced. A gendered pattern on preventive prac­tices against mycotoxin contamination on farm and in sto­rage was not clearly established. Women were main decision-makers with respect to dairy cow diets and what to do with mouldy foods. Men were more likely than women to feed cattle mouldy maize. No clear pattern on difference in knowledge on dangers of feeding cattle mouldy feeds was established between men and women. Commercial feeds, often contaminated with mycotoxins, were fed cattle regularly but in low quantities. They are expensive but increase milk production. Most milk produced was sold and when consumed at home, it was mainly in tea, which was not given to infants. These practices reduce exposure of young children to mycotoxins, but they also reduce the potential nutritional benefits for children in dairy households. We conclude that the groups that have knowledge are not always the same that implement risk mitigation practices. This information is helpful in designing the next stage of the research project which is a quantitative risk assessment of the health impacts of mycotoxins in the Kenyan dairy value chain linked with an economic assessment of the costs of mycotoxins to the livestock and health sector. In addition this study shows that gender analysis and qualitative studies can make important contributions to risk analysis for ‘One Health’ problems

Are aflatoxins a One Health issue? Results and insights from studies on aflatoxins in the East African dairy value chains

Aflatoxins are toxic byproducts from some Aspergillus fungi, mainly Aspergillus flavus, colonizing crops before and after harvest, with preference for maize and groundnuts. In large quantities the toxins are mainly hepatotoxic, and can cause death due to liver failure. Chronic low-dose exposure has been shown to cause immunosuppression and reduced growth in animals, and has been associated with stunting in children. Aflatoxin B1 is one of the most potent natural carcinogens known, causing hepatocellular carcinoma. When animals consume aflatoxins they may have clinical symptoms, reduced productivity and performance, but our literature review suggest that there is still knowledge gaps as to how much animals are affected. In addition, aflatoxins are metabolized by the animals, and residues may persist in low levels in meat and eggs, but around 7-10% of what a dairy cow consumed is excreted as the metabolite aflatoxin M1 into the milk. Our research from Kenya show that milk may contain 140 times WHO recommended levels, and feed samples may contain almost 2000 times the legal levels in Kenya. In some of the studied villages, 100% of samples exceeded legal limits. In addition, our study on urban children shows high rates of stunting in low-income areas, and an association with the consumption of aflatoxin M1. Thus, aflatoxins are a problem affecting both humans and animals, where animals do contribute to the risks for humans, but we also discuss around the potential of animals acting as a solution for the problem as well, discussing policies and mitigation methods

Prevalence of aflatoxin in feeds and cow milk from five counties in Kenya

Mycotoxin-producing fungi contaminate food and feeds before, during and after harvest. Aflatoxins are important mycotoxins and aflatoxin B1 (AFB1) is a class 1 human carcinogen (definitely carcinogenic). Aflatoxin M1 (AFM1) is a class 2B (possible) human carcinogen. Aflatoxin B1 in feeds can decrease milk production, reduce fertility and increase susceptibility to infections. A cross-sectional study of aflatoxin contamination of milk and dairy feeds was carried out in five counties in Kenya representing different agro-ecological zones: Kwale, Isiolo, Tharaka-Nithi, Kisii and Bungoma. Dairy feed concentrates and cattle milk were collected twice (dry season and rainy season) from 285 dairy farmers in the five counties and analysed for AFB1 and AFM1, using competitive enzyme-linked immunosorbent assay (ELISA). In the five counties, the proportion of farmers who fed cattle with dairy concentrates varied from zero to 68%. The dairy feed concentrates from farmers had AFB1 levels ranging from less than one part per billion (ppb) to 9661 ppb and the positive samples ranged from 47.8 to 90.3%. The percentages of dairy feeds from farmers with AFB1 above the World Health Organization/Food and Agriculture Organization of the United Nations (WHO/FAO) limit of 5 ppb varied from 33.3% to 87.5 % while 83.3% to 100% of the feeds from retailers and 28.6% to 100% of the feeds from manufacturers exceeded the WHO/FAO limit. Aflatoxin M1 prevalence in milk was lowest in Kwale (13.6%) and highest in Tharaka-Nithi (65.1%). The proportion of milk samples with AFM1 above the WHO/FAO standard of 50 parts per trillion (ppt) varied from 3.4% (Kwale) to 26.2% (Tharaka-Nithi); the highest was 6999 ppt. This study shows that aflatoxin contamination is common in dairy feeds and in milk and concentrations may be high. This may contribute to ill health effects in both humans and animals and, therefore, there is need for better understanding of the impacts of aflatoxins in the feed–dairy value chain and appropriate interventions to control aflatoxin contamination in animal feeds

The impacts of aflatoxin standards on health and nutrition in sub-Saharan Africa: The case of Kenya

Human food and animal feed can contain many different hazards, which may be biological, chemical, or physical. In most countries, there are regulations that limit the levels of these hazards permitted in food and feed so as to protect consumers. Optimally, the levels specified in the standards should make the food safe enough for everyone to consume, and often this is done by carrying out a risk assessment, based on scientific evidence of the levels that can be considered safe and the amount of contaminated products consumed. However, for some substances, especially carcinogens, it is difficult to calculate how much is safe to consume and some groups of people, such as small children or pregnant women, may be more sensitive than the population at large. While imposition of standards is motivated by health benefits, standards also have costs. These include the costs of compliance and verification, which translate- into increased costs of purchase and reduction of the products available. In this paper we summarize current standards in sub-Saharan Africa related to aflatoxins, a priority hazard, and discuss their coherence and evidence-base. Next, using our recent research findings, we estimate the health risks of consuming foods contaminated with aflatoxins in Kenya. We also estimate the negative health and economic effects that would arise from strict application of different standards for aflatoxins. We discuss the results in light of health and nutrition goals

Mapping aflatoxin risk from milk consumption using biophysical and socio-economic data: A case study of Kenya

This research reports a mapping of aflatoxin risk in the milk value chain in Kenya using a geographic information systems (GIS) approach. The objective was to spatially locate regions at risk by taking into account biophysical and socio-economic factors such as humidity and rainfall, dairy cattle density, maize production and travel time to urban centres. This was combined with historical data of aflatoxin outbreaks obtained from literature search and geo-referenced. Median values for the datasets were then used to define the thresholds. Criteria-based mapping using Boolean overlays without weighting was implemented in the ArcGIS v10.3 platform. Areas of convergence were overlaid with regions of historical outbreaks to come up with likely locations of aflatoxin risk and target sample surveys to these areas. Higher resolution maize production and consumption data would be desirable to ensure more accurate results. The process followed in this project ensures an evidence-based and replicable methodology that can be used in other regions and with different crops. Feed and milk samples collected in the different categories identified support that this approach can be used to guide sampling and regional studies. The research also discusses the strengths and limitations of the approach

Aflatoxin B1 occurrence in millet, sorghum and maize from four agro-ecological zones in Kenya

Aflatoxin-contaminated food is a public health concern. Contamination of staple foods in Kenya has in the past led to loss of human lives as well as condemnation of large quantities of food, contributing to food insecurity. This study investigated the occurrence of aflatoxins in maize, millet and sorghum from five counties in Kenya (Kwale, Isiolo, Tharaka-Nithi, Kisii and Bungoma) representing four agro-ecological zones (AEZs). Samples were collected from rural households in two phases between February and October 2014. Using competitive enzyme-linked immunosorbent assay (ELISA), 497 maize, 205 millet and 164 sorghum samples were screened for the presence of aflatoxin B1. Overall, 76% of maize, 64% of millet and 60% of sorghum samples were positive for aflatoxin B1. Of these, the proportion of samples with aflatoxin B1 levels above the Kenya Bureau of Standards limit of five parts per billion was 26% for maize, 10% for millet and 11% for sorghum. In samples collected during the second phase, there were significant differences in the mean levels of aflatoxin contamination between the agro-ecological zones (p<0.05); maize from Kisii and Bungoma, representing temperate AEZ, had the lowest mean contamination, whereas millet and sorghum from Tharaka-Nithi (humid) and Isiolo (semi-arid), respectively, had the highest mean contamination. Continued exposure to aflatoxins via food in Kenya poses a threat to human health