Costs of aflatoxin in the Kenyan dairy value chain

Kenya's dairy industry plays an important economic role in the life of farmers, milk processors, milk traders, feed manufacturers and traders. This industry contributes 14% of the agricultural gross domestic product (GDP) and 3.5 % of the total GDP. In Kenya, the dairy sector, and especially milk production, is exposed to different risk contamination factors which will not only affect the product quality but also its innocuity. Economic costs of aflatoxin contamination could be split into two categories: direct market costs and human health costs. Using agro-ecological zones, five counties in Kenya — Kwale, Isiolo, Tharaka Nithi, Kisii, and Bungoma — were selected randomly for this study. For direct costs, questionnaires were directed to feed retailers, milk producers, milk traders and feed producers. Food and feed samples (99 dairy feed, 286 milk, 386 staples (maize, millet, sorghum groundnuts and cassava) were collected for laboratory aflatoxin analysis (ongoing) to estimate the aflatoxin daily consumption rates in people and dairy cattle. In the case of health costs, primary and secondary data are being collected to assess the estimated cost of aflatoxin in Kenya. Following Rico-Sole (2012) and introducing an additional weighting factor related to the proportion of aflatoxin provided by milk consumption, the health expenditure costs related to aflatoxin through milk will be estimated. It is possible to assess health costs using secondary data provided by the national health statistics in Kenya (health expenditure, diseases, number of the population, number of exposed population etc.) and fixing values for the remaining variables on the basis of literature review. However, the uncertainties about the actual health impacts of aflatoxin exposure in a population make it difficult to fully evaluate the burden. The approach in this study follows the risks of exposure at different steps in the dairy value chain and includes consumer surveys. This will provide increased knowledge about the risks and a basis for improved assessments of the costs

Aflatoxin M1 survey in dairy households in Kenya

Kenya has the largest dairy herd and highest per capita milk consumption in east Africa. Kenya has also experienced multiple aflatoxicosis outbreaks in recent years, and several surveys have reported high levels of contamination in maize. When lactating cows consume feed which is contaminated with aflatoxins, they excrete a metabolite (aflatoxin M1) in their milk. This metabolite is injurious to human health, but there is no current information on the risk to human health posed by aflatoxins in milk in Kenya. To fill this gap, a risk assessment is being conducted in four agroecological zones in Kenya (semi-arid, temperate, sub-humid and humid). In 2014, we conducted a survey of households in these four zones. We surveyed 286 households in 37 villages and in each household administered a questionnaire and collected feed and milk samples. In all, 280 milk samples were analyzed using competitive ELISA. The limit of detection was 2 parts per trillion (ppt). Overall, 59 per cent of all samples had aflatoxin below the limits of detection, 32 per cent of samples had aflatoxin between 2 ppt and 50 ppt while 9 per cent exceeded the WHO/FAO limit of 50 ppt

PREVALENCE OF AFLATOXIN IN FEEDS AND COW MILK FROM FIVE COUNTIES IN KENYA

ABSTRACT 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 6999ppt. 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

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

Growing Problem of Multidrug-Resistant Enteric Pathogens in Africa

A disproportionate number of low-income persons are affected

Initial adherence of EPEC, EHEC and VTEC to host cells

Initial adherence to host cells is the first step of the infection of enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains. The importance of this step in the infection resides in the fact that (1) adherence is the first contact between bacteria and intestinal cells without which the other steps cannot occur and (2) adherence is the basis of host specificity for a lot of pathogens. This review describes the initial adhesins of the EPEC, EHEC and VTEC strains. During the last few years, several new adhesins and putative colonisation factors have been described, especially in EHEC strains. Only a few adhesins (BfpA, AF/R1, AF/R2, Ral, F18 adhesins) appear to be host and pathotype specific. The others are found in more than one species and/or pathotype (EPEC, EHEC, VTEC). Initial adherence of EPEC, EHEC and VTEC strains to host cells is probably mediated by multiple mechanisms