Aflatoxins contamination in processed cassava in Malawi and Zambia

Strains of the Aspergillus fungi, especially A. flavus and A. parasiticus, primarily produce aflatoxins which are a major health concern to man and livestock because of their acute and chronic health effects. Aflatoxins pose the greatest risk to health in tropical Africa because of their widespread prevalence and high toxicity; carcinogenic (cause liver and esophageal cancer) effect, immune system suppressing and anti-nutritional  contaminants in many food commodities and even cause death. Aflatoxins have also been reported to compromise vaccine efficacy in experimental animals. Due to the seriousness of aflatoxins, international agencies have restricted levels of aflatoxins to 20 ppb in food materials as the maximum permissible level in the United States and 4 ppb total aflatoxins and under 2 ppb aflatoxin B1 in Europe. These regulations directed at minimizing human exposure to aflatoxins results in severe economic loss to producers, processors and marketers of the contaminated crop. A study was conducted in Malawi and Zambia to assess the level of fungal and mycotoxins’ contamination in commonly processed cassava products. A total of 92 and 88 samples of processed cassava products comprising makaka, flour, kanyakaska, kadonoska, scrapes and grates were collected in the rainy season of 2008 and 2009 in Malawi, respectively. Further, 22 samples of processed cassava products comprising dried cassava chips and flour were collected in the rainy season of 2009 in Zambia. The samples were analyzed for fungal and aflatoxins B1, B2, G1 and G2 contamination using the Romer mini-column method and the VICAM AflaTest  immunoaffinity fluorometric method. None of the samples in 2008 were contaminated with aflatoxins. Similar results were obtained in 2009 with almost all the samples in Malawi and Zambia having aflatoxin levels much lower (<2.0 ìg/kg in Malawi and <4.2 ìg/kg in Zambia) than the Codex Alimentarius Commission (CAC) maximum permissible level of aflatoxins of 10.0 ìg/kg, implying that the cassava products analyzed were safe for human consumption. However, further studies are needed to cover a larger sample size over a period of a year to represent all seasons in the cassava producing and consuming areas and conclusively make certain the safety of these products for human consumption.Key words: Cassava, consumption, aflatoxin, food, safet

Evaluation of cassava processing and utilization at household level in Zambia

Open Access Article; Published online: 15 Jan 2019Cassava (Manihot esculenta Crantz) is the second most consumed staple food crop after maize in Africa and is the main food security crop after maize in Zambia. A study, aimed at analyzing cassava processing and utilization at household level in Zambia, was conducted. Surveys were conducted in five districts (Kasama, Samfya, Mansa, Serenje and Kaoma). A structured questionnaire was administered to a total of 300 randomly selected households. The percentage of households that were involved in processing were 4.3% for income, 34% for consumption and 58% for both income generation and consumption. Levels of awareness and usage of improved cassava processing methods across the districts were low, ranging between 20% and 26%. The only improved processing equipment that farmers used often (69%) was the hammer mill. Product development and utilization were still at a low level (ranging between 9% and 18%) in Zambia. Cassava is mostly consumed in its traditional form for its leaves, as a snack, and for preparing nshima (cassava flour alone or a mixture of cassava and maize meal, called maize-cassava nshima). The limited knowledge of cassava products’ diversity and the low usage of improved equipment are challenges to the production of confectionery products that could lead to increased cassava consumption. There has been no significant change over the last two decades in cassava processing and product development, which could spur cassava development. This calls for more efforts to support Government policy in diversifying crop use and crop diversification in order to create wealth

Manual for sweetpotato pre‐basic seed production using the sandponics system.

This manual explains the procedures involved in setting up the sandponics system and managing it to multiply sweetpotato pre‐basic seed to ensure a dependable supply of high‐quality planting materials

Determining the pan-African sweetpotato virome: Understanding virus diversity, distribution and evolution and their impacts on sweetpotato production in Africa.

Food security remains a huge challenge for the millions of Africans dependent on agriculture for their subsistence. A low-level agricultural productivity and a high percentage of poor and undernourished people are common in Africa, particularly in sub-Saharan Africa (SSA). Sweetpotato, Jpomoea batatas (L.) Lam. (Family Convolvulaceae), is among the most important food crops in the world and an extremely important food crop for subsistence farmers in SSA. It is grown throughout the African continent and currently around 34.5% of global sweetpotato area is in Africa. SSA produces approximately 7 million tons of sweetpotato annually, only about 5% of global production. One major limitation in sweetpotato production is cultivar decline, mostly due to the cumulative effect of virus infection on this vegetatively propagated crop. Thus, viral diseases are nhbconsidered a major limiting factor in sweetpotato production woridwide, and particularly in SSA. However, there is a widespread lack of basic information and understanding of virus populations throughout Africa, even though such basic information is required to manage the spread and impact of these viral diseases. This project will focus on evaluating a novel approach, deep sequencing and assembly of small RNAs from field-grown sweetpotato samples collected throughout Africa, to systematically and efficiently identify virus genome. A Pan-African sweetpotato virome will be established, which will provide the scientific community and government unprecedented possibilities to understand sweetpotato virus distribution in Africa, guide phytosanitory requirements, predict risks of future epidemics, and suggest regional disease management strategies. In West-Africa the survey is expanded to include Cassava, Banana, Yams and Potato

Exploring climatic resilience through genetic improvement for food and income crops

Plant breeding has been one of the main drivers of crop yield gains during the past century. Breeding for yield improvement through resistance to pests and diseases and chemico-physical constraints to crop production has contributed immensely to food security, nutrition, and improved incomes across Africa. Achievements through breeding have not been evenly spread across the entire range of crops grown in southern Africa. In addition, in some locations climate change threatens to reverse some of the gains from improved crop cultivars. The aim of this chapter is to analyze the progress made to date through breeding and to put forward models, which will enable farmers to benefit from breeding products both developed in the recent past and future products in the various breeding pipelines. Breeding for multiple stresses has been improved through molecular breeding techniques; however, the results are yet to benefit smallholder farmers who are the intended beneficiaries and the end users. Drought and extreme temperature-tolerant cultivars have higher chances of sustaining crop production in southern Africa. Reducing bureaucracies in seed release and moving beyond research-biased participatory varietal selection methods are two steps that require enhancement to improve and increase adoption rate of new breeding products

Occurrence of the sweet potato hornworm Agrius convolvuli (Lepidoptera: Sphingidae) in the Haut-Katanga province, Democratic Republic of the Congo

peer reviewedAgrius convolvuli (Lepidoptera: Sphingidae) is a pest that feeds on young sweet potato leaves causing severe plant defoliation. This study was designed to report for the first time on the occurrence of the pest in the Haut-Katanga province in DR Congo. Survey and observations were conducted during the growing season in ten cities of the Haut Katanga province to detect the presence of A. convolvuli. Fifty-two sweet potato fields were inspected during the season. Larvae and pupae were collected in each city and reared in the laboratory at the University of Lubumbashi, DR Congo. Results revealed that the pest occurs in the province with Lubumbashi and Kasumbalesa being the most highly infested with 18.80±11.36 and 18.71±8.13% of infestation, respectively. The highest number of larvae per field and per plant was recorded in Lubumbashi alone with 18.80±8.04 and 3.80±1.48, respectively. Classification of sweet potato leaf damage indicated that Kasumbalesa, Sakania and Lubumbashi had high levels of damage. Positive relationships were observed between infestation rate and number of larvae per field (R2=0.3069; t=4.705; p<0.0001) but also between infestation rate and number of larvae per plant (R2=0.4478; t=6.368; p<0.0001). The findings of the current study suggest that A. convolvuli could be a potential threat to sweet potato production in the Haut-Katanga province