Lactic acid‐producing bacteria (LAB) isolated from fowl, fish intestines and mushroom were identified and characterized with reference to the production of bacteriocins and its genetic markers. Among the isolated cultures, two isolate each ofLactobacillus caseissp casei C‐40 and M‐50,Pediococcus pentosaceusC‐6 and M‐10, andPediococcus acidilacticiC‐20 and F‐58 and one isolate ofPediococcussp. F‐7 were potent producers of bacteriocin active against related strains of LAB. With reference to the genetic characterization of bacteriocin production, the potent cultures appeared to posses either one or two plasmids of 4–8 Kb size and a megaplasmid. Plasmid curing of bacteriocinogenic strain ofLact. caseissp. casei C‐40 resulted in the loss of bacteriocin production and an altered pattern of sugar utilization. Antibiogram of bacteriocinogenic cultures of LAB and bacteriocin indicators was carried out to evaluate as a markers in genetic characterization. The bacteriocinogenic cultures were resistant to most of the antibiotics, particularly those belonging to the ß‐lactam and cephalosporin groups. Besides, most of these cultures were sensitive to 30 μg of chloramphenicol and 15 ng of erythromycin. The potential role of bacteriocinogenic LAB is significance in maintaining the intestinal environment, however; sensitive/resistance to antibiotics is to be viewed with concern as feeds do contain antibiotics.