Microbial diversity and dynamics of fruit-flavored traditional yoghurt ‘Ergo’ in Southern Ethiopia

This study investigated the microbial diversity, dynamics and sensory acceptance of fruitflavored traditional Ethiopian yoghurt, ‘Ergo’, supplemented with fruit juices from mango (Mangifera indica), papaya (Carica papaya), and avocado (Persea Americana, a source of Zn). Ergo samples were collected from Hawassa and Yirgalem in Southern Ethiopia. Fruit juices (mango and papaya) were substituted into Ergo at 0%, 5%, 10%, 15%, 20% and 25% (v/v) concentrations. Sensory analysis was conducted, and the lactic acid bacteria (LAB) involved in the fermentation process were characterized using Rep-PCR and 16S rRNA gene sequencing on the 15% mango formulation (the most preferred) and the control Ergo. The results revealed that Lactobacillus and Enterococcus were the predominant genera involved in Ergo fermentation, and their diversity and distribution were influenced by location and the duration of fermentation. Of the 234 LAB isolates identified, Limosilactobacillus fermentum (24.36%) and Enterococcus songbeiensis (18.37%) were the most abundant, while Lactiplantibacillus plantarum was the lowest (0.85%). Enterococcus faecalis was exclusively isolated from Yirgalem Ergo, whereas Lentilactobacillus parabuchneris was found only in Hawassa Ergo samples. Limosilactobacillus fermentum predominated on day 4 (F4) of Ergo fermentation in Hawassa (28%), and on day 2 (F2) in Yirgalem (37.5%). The findings open perspectives on the possible use of autochthonous LAB species as starter cultures for optimizing the fermentation processes and scaling up Ergo production in Ethiopia.