Evaluation & characterization of isolated lactobacillus spp. from market dahi available in Bangladesh

Abstract

This study was carried out to evaluate and compare the quality of ten types of dahi available in the local markets of Chattogram metropolitan area, Bangladesh. These samples were collected randomly and analyzed for physicochemical and microbiological properties. Physicochemical analysis includes smell, taste, body and consistency, color, texture, and acidity. Microbial analysis was also performed to check the total viable count of bacteria of dahi. In addition, an attempt was made to isolate lactic acid bacteria (Lactobacillus sp.) from local Dahi through the phenotypic characterization method. The organoleptic analysis showed that the highest mean value of total score was found in Sizzle brand (80±9.57) and the lowest mean value was found in Aarong brand (66.5±6.30). In most of the cases, Sizzle and Bonoful brands obtained the highest marks in score card but in the case of chemical test, the highest acidity percentage was obtained by Shakti plus (0.95±0.09), the lowest acidity was found in case of Sizzle brand dahi (0.61±0.02). The acidity percentage of Shakti plus exceed the standard level of acidity of dahi which might be due to uncontrolled incubation, postproduction handling, and prolonged storage. Microbial analysis of dahi showed that the highest total viable count of bacteria was found in case of Kutumbari restaurant dahi (54±30.94×103) CFU/ml, and the lowest value was found in the case of Khulshi Mart dahi (24±11.77×103) CFU/ml. In this study, Lactobacillus spp. were isolated and identified from these local market dahi. They can survive in high concentrations of salt and low concentrations of phenol. During the experiment period, Sizzle dahi had a good quality compared to other dahi tasted. Comprehensive research work is still required to set a standard for microbial quality to produce superior quality dahi in Bangladesh. In this study, Lactobacillus spp. were identified by phenotypic characterization method from local market dahi.