Identification and Characterization of Lactobacilli from Rajshahi Traditional Curds

Abstract

The popular food, dairy products like curds are consumed by many people in its various forms in Bangladesh. Infact, these different types of curds are made without real respect for basic standards of technology and hygiene. This situation will be improved if lactic ferments are well-identified and their synergy taken into consideration. Not much information has been reported about the Lactobacilli species responsible for curd production in Bangladesh. In this context, this study was conducted to identify and characterize lactic acid bacteria in curds to provide scientific data needed for improvement of the fermented product. Twenty samples were collected from the producers of curds in the supermarket of Shaheb Bazar, Rajshahi. The culture media used were Czapek Dox (pH 5.3), M17, MRS and nutrient broth and agar for the investigation of lactic acid bacteria. The identified lactic acid bacteria were Lactobacilli including Lactobacillus casei (sample 1), Lactobacillus delbrueckii (sample 3), Lactobacillus plantarum(sample 4) and Lactobacillus helveticus (sample 6) based on morphological characteristics, catalase activities, milk coagulation, growth at different temperature, growth in medium with different NaCl concentrations, growth at different pH, carbohydrate fermentation profiles, exopolysaccharides production, resistance to antibiotics and other biochemical tests. The results of this work will help in the production of dairy products with better quality and longer shelf-life. The isolation of lactic acid bacteria particularlyLactobacilli could be a good tool for information to improve the characteristics of curds and hygienic quality of the dairy products.