Aflatoxin in household maize for human consumption in Kenya,East Africa

ABSTRACT

The objective of this study is to determine the occurrence and level of aflatoxins (AFs) contamination in freshly harvested maize for human consumption in rural Kenya. Maize kernels and freshly milled maize flour (n = 338) were collected from households in Siaya and Makueni counties. While both counties are representatives of different environmental and climate conditions, Makueni County is the area with reported outbreaks of aflatoxicosis. Samples were analysed for AFB₁, AFB₂, AFG₁, and AFG₂ using Ultra High-Pressure Liquid Chromatography with Fluorescence detection. AFs were detected in 100% of the samples with the range of 2.14–411 µg/kg. The geometric mean of total AFs in all samples from Makueni County is 62.5 μg/kg with 95% CI: 53.7, 71.4 while in Siaya County is 52.8 μg/kg with 95% CI: 44.0, 61.7. This study showed that AFs contamination is prevalent in maize-based foods in the region.     

Technology adoption and the multiple dimensions of food security: the case of maize in Tanzania

The paper analyses the impact of agricultural technologies on the four pillars of food security for maize farmers in Tanzania. Relying on both matching techniques and endogenous switching regression models, we used a nationally representative dataset collected over the period 2010/2011 to estimate the causal effects of using improved seeds and inorganic fertilizers on food availability, access, utilization, and stability. Our results show that the adoption of both technologies have positive and significant impacts on food availability while for access, utilization and stability we observe heterogeneity between improved seeds and inorganic fertilizers as well as across the food security pillars. The study supports the idea that the relationship between agricultural technologies and food security is a complex phenomenon, which cannot be limited to the use of welfare indexes as proxy for food security.     

Progress in protein quality of maize

The protein quality of some improved protein quality maize varieties grown in Mexico was measured chemically (including amino acid analyses) and biologically, in N-balance experiments with growing rats. The protein content ranged from 10.61 to 12.84%. Lysine 100 g^?1 protein varied between 2.63% for a normal variety to 4.18% for one of the improved varieties. The tryptophan content in the improved varieties was increased by 40-100%. There was a highly significant (P<0.001) positive correlation (r=0.98) between biological value and lysine 100 g^?1 protein whereas the relationship between protein and available carbohydrate was not significant. True protein digestibility was very high and above 95% in all samples. Biological value, however, was higher by 10-15 percentage units in the improved materials compared to the normal maize.     

Assessment of protein nutritional quality and effects of traditional processes: a comparison between Ethiopian quality protein maize and five Ethiopian adapted normal maize cultivars

The present study was designed to quantitatively measure and compare the levels and variations of total protein, individual amino acids, and computed protein efficiency ratio (C-PER) in raw and traditionally processed products of one recently released quality protein maize (QPM BH542) with four high-yield maize hybrids, namely flint BH660, semi-dent BH140, Pioneer 30H83, and Pioneer 30G97, as well as one local maize cultivar. The total protein content was variable among the cultivars ranging from 7% for BH660 to 8.6% for Pioneer 30H83, 8.9% for BH140, 9.8% for QPM BH542, 10.1% for local maize cultivar, and 11.8% for Pioneer 30G97, respectively. However, the QPM BH542 maize protein proved to be higher in nutritional quality than common maize proteins because it contained 30% to 82% more lysine, higher levels of arginine, tryptophan, histidine, threonine, cysteine, and valine. As a result, the QPM BH542 amino acid profile gives a good balance of total essential amino acids, limited only in lysine, and has a C-PER ratio of 2.2 compared to 1.14, 1.2, 1.4, 1.66, and 1.67 for Pioneer 30G97, local, BH-140, BH660, and Pioneer 30H83, respectively. The various traditional processes of maize have no significant effect on the protein nutritional quality of the new quality protein maize. Hence, the widely dissemination of it in agricultural cultivation as well as consumption by the general population is recommended.     

Narrowing the gap: Practical strategies for increasing whole‐grain consumption

Overcoming consumer confusion and doubt regarding nutrition recommendations is key to communicating the message to increase whole‐grain foods in the diet. Nutrition communicators may do that more successfully by using four tactics to fashion messages about whole grains: (1) present a positive message; (2) keep it short and simple; (3) keep the message practical and flexible; (4) speak with a united voice. The quantitative recommendation to eat at least three servings of whole‐grain foods daily also must be integrated into national nutrition documents, such as Healthy People 2000, Dietary Guidelines for Americans, the Food Guide Pyramid, Nutrition Recommendations for Canadians, and Canada's Food Guide to Healthy Eating, if we are to be truly successful in communicating the need to increase whole‐grain consumption.     

Field effectiveness of improved hermetic storage technologies on maize grain quality in Central Mexico

Maize is the main crop cultivated by small scale farmers (SSF) in Mexico, and its production represents an important goal for local food security. However, SSF very often face severe post-harvest losses in maize, mainly because of insect pests and the lack of suitable storage technology. This study was conducted to compare the field effectiveness in terms of maize quality under on-field conditions of SSF of two improved hermetic storage technologies with the traditional storage. The field experiment was performed on-farm in the highlands of Central Mexico. Maize grains were stored in three storage devices: hermetic plastic bag (sBag), hermetic plastic silo (Bioxilo), or traditional polypropylene sacks. The study considered the quantitative evaluation of storage, physical, nutritional, and industrial qualities of maize after 4, 8 and 12 months of storage. Environmental conditions of storage such as oxygen levels, temperature and humidity were monitored. After 1 year of field storage, compared with traditional sacks, sBag and Bioxilo showed a significant lower losses in storage due to insects. When controlled infested maize by artificial insect infestation methods was used, the improved technologies were also effective in reducing grain losses. Furthermore, both sBag and Bioxilo prevented grain quality detriment in terms of physical, nutritional and industrial (for tortilla and seed) properties (p < 0.01). Additionally, compared with traditional storage, sBag and Bioxilo showed efficient control of the hermetic conditions in terms of oxygen, temperature and humidity, but no significant differences were detected between the two improved technologies. In summary, under on-farm conditions, the successful preservation of maize grain quality was achieved by the improved sBag and Bioxilo in the highlands of Mexico. In the future, positive effects of this storage system will need to be validated under tropical conditions.     

The effectiveness of palate cleansing strategies for evaluating the bitterness of caffeine in cream cheese

The objective of this study was to compare the effectiveness of seven methods used to cleanse the palate including: water, sparkling water, carrots, crackers, plain cream cheese, and rinsing six times or not at all before evaluations. Twenty subjects rated the bitterness intensity of cream cheese samples varying in caffeine content. Each participant completed seven sessions, using a different palate cleanser in each session. We found no differences in the effectiveness of these palate-cleansing strategies for their ability to control adaptation and build-up, or for their ability to increase panelists' discrimination among samples. Rinsing with sparkling water depressed the perceived bitterness at all levels of caffeine.     

Post-harvest losses in African maize in the face of increasing food shortage

Maize is the most important food staple for resource-poor smallholders in Africa, providing food and income to millions. One of the key constraints to improving food and nutritional security in Africa is the poor post-harvest management that leads to between 14 % and 36 % loss of maize grains, thereby aggravating hunger. Post-harvest losses contribute to high food prices by removing part of the supply from the market. Reducing post-harvest losses in maize is an essential component in any strategy to make more food available without increasing the burden on the natural environment. Solving the post-harvest management problems in maize will require cooperation and effective linkage among the following: research, extension, agro-industry, marketing system and favorable policy environment. Biological and socio-economic causes of post-harvest losses in maize in Africa are discussed in relation to climate change and food security, and strategies to reduce the post-harvest losses are suggested.     

The case for milk protein standardisation using membrane filtration for improving cheese consistency and quality

Milk composition varies with season owing to stage of lactation and variation in diet and weather. Variation in the concentration of milk protein is conducive to inconsistency in cheese yield, composition and quality especially where standard operating procedures are not objectively standardised with reference to casein content. Milk protein standardisation (e.g. to 4.5%) by low‐concentration factor ultrafiltration (LCFUF) or microfiltration (LCFMF) provides an effective means of obtaining more consistent cheese manufacture. Consequently, LCFUF is now widely practised. The benefits of LCFUF and LCFMF and the effect of key processing parameters on the quality of cheese from protein‐standardised milk are reviewed.     

The use of sensory evaluation and consumer preference for the selection of sweetpotato cultivars in East Africa

Sweetpotato is an important staple crop in East Africa with great potential for introducing improved cultivars, but little is known about which sensory characteristics are desirable. Over a 2 year period, 600 consumers were interviewed at three locations (urban and rural) in the Lake Zone of Tanzania and their preference of 14 locally available sweetpotato cultivars in cooked form was evaluated. A simple questionnaire based on consumers first‐choice preference was used followed by socio‐economic questions. A trained sensory panel profiled the cooked sweetpotato samples, enabling comparisons with preference, location and season. Cluster analysis based on the sensory attributes was used to classify the cultivars into three groups; one cluster comprised the most preferred cultivars and another contained the least. Some cultivars were consistently preferred over the 2 year period while others were not. The location where the cultivars were grown also influenced preference. Stepwise regression indicated that the most discriminating sensory attributes were starch and stickiness. Target levels based on the mean intensity scores of these attributes are suggested as a means of screening new cultivars. The implications of these findings are discussed. Copyright © 2004 Society of Chemical Industry     

Improved production systems for traditional food crops: the case of finger millet in western Kenya

Increasing agricultural productivity through the dissemination of improved cropping practices remains one of the biggest challenges of this century. A considerable amount of literature is dedicated to the adoption of improved cropping practices among smallholder farmers in developing countries. While most studies focus on cash crops or main staple crops, traditional food grains like finger millet have received little attention in the past decades. Traditional food grains have however an important potential to improve food security, reduce micronutrient deficiencies, and enhance smallholder adaptation to climate change. The present study aims to assess the factors that influence adoption decisions among finger millet farmers in western Kenya. Based on cross-sectional household data from 270 farmers, we estimated a multivariate probit model to compare the adoption decisions in finger millet and maize production. While improved practices such as the use of a modern variety or chemical fertilizer are relatively well adopted in maize production, they are less common in finger millet production. Social networks as well as access to extension services play crucial roles in the adoption of improved finger millet practices, while the same variables are of minor importance for the adoption of improved maize practices. A Cobb-Douglas production function shows a positive effect of modern varieties and chemical fertilizer on finger millet yields.