Neeragaram (fermented sour beverage) is a traditional energy drink of Tamil Nadu and is considered to contain a variety of beneficial bacterial species. The purpose of this study was to isolate and identify bacteria from samples of ethnic fermented sour beverages, particularly lactobacillus species. The red rice varieties of Tamil Nadu have been chosen for developing the beverages. The samples were ADT 43 as control beverage, mapillai samba as treatment 1 and karungkuruvai as treatment 2 for developing fermented sour beverages. Three bacterial isolates, Isolate 1, Isolate 2 and Isolate 3 were isolated from fermented sour beverages and identified using morphological and biochemical assays. The two isolates were gram-positive, non-motile, round-shaped bacteria. The isolated bacteria were examined with multiple media including Mannitol Salt Agar, MacConkey Agar, EMB Agar, TSI Agar, Simmons Citrate Agar, Urea Agar, BSA, and Starch Agar with Catalase assay for biochemical characterization. Both morphologically and biochemically, the isolates have been identified as Leuconostoc mesenteriodes. By using the disc diffusion method as well as twelve different antibiotics, the isolates were further evaluated for their antibiotic sensitivity. Three of the antibiotics aztreonam, ampicillin and penicillin were all resistant to the isolated bacteria, whereas four of the drugs imipenem, ciprofloxacin, rifampicin and doxycycline were all susceptible. According to this study, it can be concluded that Leuconostoc mesenteriodes could be found in the ethnic fermented sour beverages which acts as a probiotic source to heal many stomach-related disorders.