Does Exposure to Aflatoxin Constrain Efforts to Reduce Stunting in Zambia?

On 8 June 2013, the Vice President of Zambia stated that his government ‘is fully committed to reducing chronic undernutrition by 50 per cent in the next ten years…’ What are the challenges to meeting this goal? Zambia has both a high consumption of groundnuts and high levels of aflatoxin contamination of this commodity. Recent studies indicate an association between stunting and aflatoxin exposure. If the association exists, then Zambia faces serious challenges to reaching its target of 50 per cent reduction in chronic undernutrition. Recent efforts to identify atoxigenic strains for biocontrol in maize and groundnuts give cause for cautious optimism. Nonetheless, the challenges ahead demand both a high level of political will to achieve effective multisectoral collaboration and the willingness of the agricultural and health sectors to undertake rigorous monitoring of aflatoxin contamination and growth of young children, as well as the agricultural sector’s commitment to reduce substantially levels of aflatoxin contamination and to promote agricultural diversification

Microbial population dynamics during traditional production of Mabisi, a spontaneous fermented milk product from Zambia : a field trial

Mabisi is a fermented milk product, traditionally produced in a calabash by uncontrolled fermentation. Due to high costs and a reduced availability of calabashes, nowadays plastic containers are also used for Mabisi production. However, the effect of this change in production practice on the properties of the product has not been documented. Therefore, we aimed at determining the effect of fermentation vessels and types of back-slopping on acidification and microbial communities during fermentation. A series of fifteen experiments using two types of fermentation vessels (plastic buckets and calabashes) in combination with different types of back-slopping (no back-slopping, passive back-slopping, and active back-slopping) were set up at a field site in rural Zambia. In each of the fifteen fermentations we analysed acidification rate of traditional Mabisi fermentation and bacterial diversity over time. No significant difference was found in terms of microbial diversity during and at the end of fermentation between fermentations performed in buckets or previously used calabashes. Bacterial communities in general decreased in diversity over time, where the drop in pH correlated with a decrease in Shannon Index. In case of active back-slopping, the pH drop started right after inoculation while in the no back-slopping and passive back-slopping fermentations, there was a clear lag phase before acidification started. All experimental series resulted in a microbial community dominated by Lactococcus lactis and a Shannon Index, as a measure for diversity, between 0.6 and 2.0. The use of plastic buckets for Mabisi fermentation can be a valuable alternative to the use of calabashes as this study showed no biological and physico-chemical differences between Mabisi resulting from both fermentation vessels, although the reason for perceived differences should be further investigated

Towards valorisation of indigenous traditional fermented milk : mabisi as a model

Africa has a rich cultural heritage that is accompanied by rich traditional foods. Some of these foods are preserved by traditional fermentation processes, which are transferred from one generation to another. Fermentation is a low-cost technology, which converts raw materials into final products with improved nutritional value, organoleptic properties and extended shelf life. These traditional fermented foods are widely consumed in both rural and urban areas. This review uses mabisi, a traditional fermented milk product from Zambia to demonstrate the importance of indigenous knowledge of mabisi processing in the valorisation process with a view towards upscaling of not only mabisi but also other similar traditional food products. It highlights the different types, product characteristics and microbial communities of mabisi

Fermented cereal-based Munkoyo beverage: Processing practices, microbial diversity and aroma compounds

Fermented cereal-based foods play a crucial role in attaining food and nutrition security for resource-poor populations in sub-Saharan Africa. These products are widely produced by spontaneous fermentation using of cereal grains as raw material. They have a unique taste and flavour, are rich sources of energy and their non-alcoholic nature makes them ideal for consumption by the entire population, including children. Lactic acid bacteria dominate the fermentation process and lead to a low pH of around 4, which suppresses the growth of pathogenic bacteria, thereby increasing the shelf-life and safety of the food. Knowledge about processing practices, consumption patterns and bacterial communities is essential to regulate processing and design appropriate mixes of micro-organisms to produce starter cultures for commercial production of standard-quality fermented foods that meet desired quality characteristics. In four regions of Zambia, we surveyed processing practices and consumption patterns of a spontaneously fermented cereal-based beverage called Munkoyo, commonly produced in Zambia and the Democratic Republic of Congo. Variations in processing practices exist in cooking time of the unfermented maize porridge and time allowed for fermentation. Consumption is mainly at household level and the product is considered as an energy drink. Characterisation of the bacterial communities of over 90 samples with 16S amplicon sequencing on DNA extracted from the entire bacterial community revealed six dominant families, namely Streptococcaceae, Leuconostocaceae, Enterobacteriaceae, Lactabacillales, Bacillaceae and Aeromonadaceae, and a Shannon index of up to 1.18 with an effective number of 3.44 bacterial species. Bacterial communities that underlie the fermentation in Munkoyo differ in their composition for the different regions using common processing steps, suggesting that different combinations of bacteria can be used to achieve successful Munkoyo fermentation. Analysis of aroma profiles in 15 different samples from two different Provinces showed that aldehydes, esters, organic acids, alkanes, alkenes and alcohols dominated.</p

The art of mabisi production : A traditional fermented milk

Fermented dairy products can be rich in beneficial microbes and one such product with potential is mabisi. Mabisi is a traditional fermented milk product from Zambia made through spontaneous fermentation of raw milk at ambient temperature using a calabash (gourd), clay pot, plastic or metal container. The fermentation takes about 48 hours after which the product is stirred and ready for consumption. This study was aimed at determining the types of production methods of mabisi and identifying the critical production process parameters. A survey was conducted using interviews and observations to determine the existing production practices/technologies and to capture indigenous knowledge on mabisi production in nine provinces of Zambia. We found seven different production methods which we coined; Tonga, thick-Tonga, illa, barotse, backslopping, cooked and creamy types. Interestingly, the Tonga-type mabisi was produced throughout the country by different ethnic groups. The main process parameters were found to be fermentation time and temperature, type of containers, presence/absence of backslopping, agitation, heating and cooling, removal of whey and addition of raw milk. And further found that mabisi is a versatile product consumed with a wide variety of foods. This basic information is crucial for production process optimisation and microbial communities dynamics studies.</p

How processing methods affect the microbial community composition in a cereal-based fermented beverage

Traditionally fermented beverages significantly contribute to food security in Africa. The nutritional and sensory quality characteristics of these beverages are closely linked to the different microorganisms they contain. We studied the effect of processing methods on the microbial composition of Munkoyo, a cereal-based fermented beverage, in three Zambian agroecological zones. In Choma, porridge was made from maize grits to which a watery extract from Rhynchosia roots was added as a source of enzymes. In Nyimba, maize meal was used to make porridge, in which Rhynchosia roots were submerged overnight. In Kitwe, porridge from maize meal was cooked until caramelization, followed by submersion of Rhynchosia roots. Irrespective of processing method, final pH was 2.5–3.5, with the lowest value for Nyimba. Presence and abundance of 16S rRNA encoding DNA sequences of the microorganisms showed no clear clustering on basis of the processing method but significantly affected the operational taxonomic unit (OTU) composition (anosim, R3,13 = 0.407, p < 0.05). The average Shannon indices, which indicate ecological diversity, were: Choma 1.14 ± 0.64, Nyimba 1.58 ± 0.23, and Kitwe 1.07 ± 0.95. Consequently, for industrial upscaling and quality standardization, specific combinations of different bacterial species can produce Munkoyo that addresses local consumer preferences.</p

Fermented cereal-based Munkoyo beverage: Processing practices, microbial diversity and aroma compounds

Fermented cereal-based foods play a crucial role in attaining food and nutrition security for resource-poor populations in sub-Saharan Africa. These products are widely produced by spontaneous fermentation using of cereal grains as raw material. They have a unique taste and flavour, are rich sources of energy and their non-alcoholic nature makes them ideal for consumption by the entire population, including children. Lactic acid bacteria dominate the fermentation process and lead to a low pH of around 4, which suppresses the growth of pathogenic bacteria, thereby increasing the shelf-life and safety of the food. Knowledge about processing practices, consumption patterns and bacterial communities is essential to regulate processing and design appropriate mixes of micro-organisms to produce starter cultures for commercial production of standard-quality fermented foods that meet desired quality characteristics. In four regions of Zambia, we surveyed processing practices and consumption patterns of a spontaneously fermented cereal-based beverage called Munkoyo, commonly produced in Zambia and the Democratic Republic of Congo. Variations in processing practices exist in cooking time of the unfermented maize porridge and time allowed for fermentation. Consumption is mainly at household level and the product is considered as an energy drink. Characterisation of the bacterial communities of over 90 samples with 16S amplicon sequencing on DNA extracted from the entire bacterial community revealed six dominant families, namely Streptococcaceae, Leuconostocaceae, Enterobacteriaceae, Lactabacillales, Bacillaceae and Aeromonadaceae, and a Shannon index of up to 1.18 with an effective number of 3.44 bacterial species. Bacterial communities that underlie the fermentation in Munkoyo differ in their composition for the different regions using common processing steps, suggesting that different combinations of bacteria can be used to achieve successful Munkoyo fermentation. Analysis of aroma profiles in 15 different samples from two different Provinces showed that aldehydes, esters, organic acids, alkanes, alkenes and alcohols dominated.</p