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Aflatoxins are toxic by-products of fungi contaminating maize and other crops; they can be carried over into milk, meat and eggs when livestock eat aflatoxin-contaminated feed or fodder. People who consume such animal products are exposed to the toxins. To assess the aflatoxin contamination status in marketed raw milk and associated risk factors in peri-urban Nairobi, we conducted a census of raw milk retailers in Dagoretti Division, Nairobi, Kenya. Structured questionnaires were filled in by face-to-face interviews with all retailers who agreed to participate in this study. Small portions of milk were purchased from each respondent and tested for aflatoxin M1 (AFM1) using competitive enzyme-linked immunosorbent assay (cELISA) tests. Geographic coordinates of each eligible retailer were recorded. A total of 350 milk retailers were visited and 344 were plotted on a map. Of these, 250 retailers answered the questionnaire and a milk sample from each of 200 retailers underwent cELISA analysis for AFM1. Four types of businesses were found: kiosks (71%), dairy shops (21%), street or mobile vendors (3%) and grocery stands (1%); for 4% the business type was not identified. Milk was mainly sourced directly from dairy farms (59%) or from intermediate distributors (35%). Most retailers sold less than 20 litres per day of raw milk. The mean daily milk consumption of the milk retailers' households was 940 ml for adults and 729 ml for children. Although 58% of retailers had heard about aflatoxins and the majority of them agreed that aflatoxins could be present in milk, only 29% believed that 'milk safety cannot be solely judged by sight or taste' and only 6% that 'milk is not completely safe even after boiling'. The cELISA test found the mean concentration of AFM1 was 128.7 parts per trillion (ppt) (median=49.9; 95% confidence interval=3.0-822.8) with a maximum of 1675 ppt. Overall, 55% of samples exceeded the European Union maximum level of 50 ppt and 6% exceeded the recommended maximum level of the United States Food and Drug Administration of 500 ppt. Compared to milk from street vendors, a significantly higher amount of AFM1 was detected in milk from kiosks and dairy shops, especially when the milk was sourced from farms without an intermediate distributor. Our findings indicate the need to better understand and manage aflatoxin in milk in Nairobi. Key words: Aflatoxin M1, Kenya, milk, dairy value chain, milk retailers, Dagoretti, mycotoxin, informal milk marketing, INTRODUCTION Aflatoxins are toxic by-products of fungi, mainly Aspergillus flavus and A. parasiticus, which contaminate maize and other crops in areas with hot and humid climates. Aflatoxin contamination is a [...]

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 agroecological zones (p Key words: mycotoxins, contamination, cereals, exposure, East Africa, aflatoxicosis, aflatoxins, seasons, INTRODUCTION Cereals, including maize, sorghum and millet, are important staple foods in Kenya. They are used as human food and animal feed and are a source of processed foods such [...]

Structural control of adjacent flexible structures has been shown to be effectively accomplished using the connected control method (CCM), which uses an auxiliary structure to provide a reaction force. A perceived constraint of the CCM is the ineffective control of structures with similar dynamics. However, the writers have presented a modified CCM mechanism in which dampers are connected between dynamically similar structures with a difference in connection height using cantilever structures. The research described in this paper extends the CCM to couple two dynamically similar structures and determines optimal stiffness and damping in the connector link. A two-degree-of-freedom building model is developed for the optimal design of the connected control devices. The optimal solutions of the connector stiffness and damping take into account the presence of fixed points in the systems transfer functions. Analytical results confirm the effectiveness of the proposed method and design. Experimental tests then verify the response reduction capabilities of the proposed optimal design. CE Database subject headings: Structural control; Seismic analysis; Passive control; Optimization; Design.