Browsing by Author "Nigatu, Ayele"

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    Taxonomic studies on Lactobacillus and Pediococcus isolates from fermented tef (Eragrostis tej) and kocho (Ensete ventricosum) and microbiological safety of the baked products
    (Addis Ababa, 1998-06) Nigatu, Ayele; Ashenafi, Mogessie (Professor)
    Tel dough and kocho are products of typical lactic acid food fennentations. BOIh foods are the main dietary sources in Ethiopia. Lactic acid bacteria (LAB) belonging to Lactobacillus. Pediococcus and LeuconslOc are amongst the main fermentative rnicroflora in these foods. Molecular taxonomic stud ies using RAPD. DNA:DNA hybridization. 16S rR.!'lA sequencing and API 50 CH fennentation profiles were carried out on food isol ates together with type and reference strains of Lactobacillus and PediococclIs species. The results revealed (he presence of a diverse range of species in ref and kocho. Lactobacillus and Pediococcus spec ies were abundant in both foods while Weissella species were identified among kocho isolates. The use of R..<\PD was valuable for grouping lactobacilli and pediococci isolates from kocho and lei The method enabled discrimination ben .... een phenotypically inseparable pediococci. Ped. acidilaclici and Ped penrosacell.s and among type strains of Lactobacillus species. Its use might however. be limited in large number of lactobacilli isolates. DNA homology and sequence data were fo und to be supplementary and essential for efficient identification of an isolate. API 50 CH utilization profiles were influenced by incubation temperature in many strains of Lactobacillus species. Diversity and higher test vigours of isolates while utilizing different carbohydrates showed pertinent metabolic roles in fermenting ref dough and kocho. The inability of different pathogenic and spoilage bacteria to survive the fermentation processes and baking heat implied the high safety levels of the products.