Retrieval of Aerosol Optical Depth Over Ecologically Stressed East African Land Surfaces from Top of Atmosphere Radiance Utilizing the Aerosol Free Vegetation Index

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Prevalence and potential for aflatoxin contamination in groundnuts and peanut butter from farmers and traders in Nairobi and Nyanza provinces of Kenya

Objective: Most of the peanut butter marketed in Nairobi is processed in cottage industry and its aflatoxin contamination status has not been documented. This study was therefore conducted to determine the status of aflatoxin contamination in groundnuts and peanut butter in Nairobi and Nyanza. Methodology and results: Eighty two fresh samples comprising raw and roasted groundnuts and peanut butter were obtained from market outlets and cottage processors in Nairobi and Nyanza regions. The marketers and processors were asked for information on the source of groundnuts. The incidence of Aspergillus section Flavi was determined using standard laboratory methods. Defective nuts in raw groundnuts were determined by manual sorting. Aflatoxin analysis was done using competitive ELISA technique. Groundnuts in Nairobi were imported from Malawi while those Nyanza were grown in the region. The fungal species isolated from the samples were: Aspergillus flavus (L and S strains), A. parasiticus, A. niger, A. tamari, A. alliaceus, A. caeletus and Penicillium spp. The percentage of defective nuts among all unsorted groundnuts ranged from 0.0% to 26.3%. The mean percent defective nuts was higher for Nairobi samples than Nyanza. Aflatoxin levels in all samples ranged from 0 to 2377.1 μg/kg. The mean aflatoxin level was higher for raw samples from Nairobi than Nyanza. The source of groundnuts and defective nuts were positively associated with aflatoxin levels. Conclusions and application of findings: The source of groundnuts and presence of defective nuts were identified as the main factors influencing increased aflatoxin contamination in the cottage industry. Mechanisms for inspection and certification of imported groundnuts should be put in place accompanied by effective monitoring for compliance to set aflatoxins standards. All the market players should sort their groundnuts before selling or processing in order to reduce aflatoxin contamination of peanut butter. Key words: Aflatoxin, cottage industry, groundnut, peanut butter. J. Appl. Biosci. 201

Farm technology adoption in Kenya: a simultaneous estimation of inorganic fertilizer and improved maize variety adoption decisions

This paper models inorganic fertilizer and improved maize varieties adoption as joint decisions. Controlling for household, plot-level, institutional and other factors, the study found that household adoption decisions on inorganic fertilizer and improved maize varieties were inter-dependent. Other factors found to influence the adoption of the two technologies were farmer characteristics, plot-level factors and market imperfections such as limited access to credit and input markets, and production risks. Thus, easing market imperfections is a pre-requisite for accelerating farm technology adoption among the smallholders. Inter-dependence of farm technologies must also not be ignored in farm technology adoption promotion initiatives

The Battle for a Sustainable Food Supply

Since the time that Homo sapiens took up farming, a battle has been waged against pests and diseases which can cause significant losses in crop yield and threaten a sustainable food supply. Initially, early control techniques included religious practices or folk magic, hand removal of weeds and insects, and “chemical” techniques such as smokes, easily available minerals, oils and plant extracts known to have pesticidal activity. But it was not until the early twentieth century that real progress was made when a large number of compounds became available for testing as pesticides due to the upsurge in organic chemistry. The period after the 1940s saw the introduction of important families of chemicals, such as the phenoxy acid herbicides, the organochlorine insecticides and the dithiocarbamate fungicides. The introduction of new pesticides led to significant yield increases, but concern arose over their possible negative effects on human health and the environment. In time, resistance started to occur, making these pesticides less effective. This led agrochemical companies putting in place research looking for new modes of action and giving less toxic and more environmentally friendly products. These research programmes gave rise to new pesticide families, such as the sulfonylurea herbicides, the strobilurin fungicides and the neonicotinoid insecticide classes