Pediococcus acidilactici strain M produced a bacteriocin which was proteinaceous, heat stable, and exhibited antimicrobial activity against lactic acid bacteria, variety of food spoilage and pathogenic bacteria. The antimicrobial activity was not caused by $H_2$$O_2$ and organic acid, and was remained between pHs of 4.0 to 9. Molecular weight of crude bacteriocin was approximately 2, 500. Phenotypic assignment after plasmid cruing experiment demonstrated that a 53.7 kilobase (kb) plasmid, designated as pSUC53, was responsible for the sucrose fermentation phenotype ($Suc^+$) and a 11.1 kb plasmid, designated as pBAC11, was associated with bacteriocin production phenotype ($Bac^+$). Neither of the two plasmids were linked to antibiotic resistance.