Microbial diversity, aflatoxin M1 contamination and potential lactic acid starters for commercially produced traditional fermented dairy beverages, a case of Bongo from Uganda
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Abstract
This was a cross sectional study that examined the microbial ecology and aflatoxin M1 contamination in commercially produced Bongo, a traditionally fermented dairy beverage from Uganda. It also involved isolation and preliminary evaluation of defined starter cultures for Bongo. Microbial analyses were done by agar plating. Microbial identification was initially done by biochemical testing and microscopy. Followed by 16S rRNA and Internal Transcribed Spacer (ITS) region sequencing for bacteria and yeasts, respectively. Community DNA was studied using Next Generation Sequencing (NGS). Aflatoxin M1 was determined using Ultra High Pressure Liquid Chromatography - Triple Quadrupole Mass Spectrometry. (GTG)5 Rep PCR fingerprinting was used to cluster candidates for starter culture evaluation. The rates of acidification of cow milk by candidate LAB coupled with sensory acceptability of the milk they fermented were the criteria for the selection of the starter cultures. Results indicated that lactic acid bacteria (LAB) and yeasts were the dominant groups. Molds, coliforms, enterococci and staphylococci were also detected. Aflatoxin M1 were insignificant. Based on agar plating technique, lactococci and lactobacilli were dominant, however, NGS showed Streptococci. Agar plating also showed Saccharomyces as dominant, but NGS showed Dipodascus. Cluster analysis identified 18 LAB, which were evaluated for starter culture properties. Three showed promise suggesting that they could be used for commercial production of cultured milks like Bongo.
期刊介绍:
The International Dairy Journal publishes significant advancements in dairy science and technology in the form of research articles and critical reviews that are of relevance to the broader international dairy community. Within this scope, research on the science and technology of milk and dairy products and the nutritional and health aspects of dairy foods are included; the journal pays particular attention to applied research and its interface with the dairy industry.
The journal''s coverage includes the following, where directly applicable to dairy science and technology:
• Chemistry and physico-chemical properties of milk constituents
• Microbiology, food safety, enzymology, biotechnology
• Processing and engineering
• Emulsion science, food structure, and texture
• Raw material quality and effect on relevant products
• Flavour and off-flavour development
• Technological functionality and applications of dairy ingredients
• Sensory and consumer sciences
• Nutrition and substantiation of human health implications of milk components or dairy products
International Dairy Journal does not publish papers related to milk production, animal health and other aspects of on-farm milk production unless there is a clear relationship to dairy technology, human health or final product quality.