Abstract : Lactobacillus plantarum IIA-1A5 is a lactic acid bacterium from local cattle of Peranakan Ongole with probiotic characteristics. This strain was found to be able to produce bacteriocin plantaricin IIA-1A5, which was proven to be able to inhibit Gram positive and negative bacteria as well as used as meat product preservative agents. Nevertheless, the stability of gene encoding plantaricin IIA-1A5 during the fermentation process remains unknown, which may reflect the stability of this strain to produce the bacteriocin along the process. This study aims to identify the presence of a gene encoding precursor of plantaricin IIA-1A5, namely PlnEF, in the buffalo meat-based fermented sausage. To address, the bacterial genomic DNA was extracted and used as a template for amplification of PlnEF gene using designated primers. A 428 bp amplicon was obtained, which showed close similarity to the PlnEF from the other plantarum strains (accession code of T028600.1, KT028601.1, and KT028602.1) with a homology of more than 99%. Interestingly, the phylogenetic tree showed that only PlnEF of KT028602.1 is located at a different branch than that of PlnEF of IIA-1A5. This result indicated a few things as follows. Firstly, IIA-1A5 strain well survives in the sausage to produce a remarkable amount of genomic DNA for amplification. Secondly, PlnEF is indeed originated from IIA-1A5 strain used as a fermentation starter. Thirdly, the PlnEF gene is found to be genetically stable during the fermentation process and might imply the IIA-1A5 strain kept being able to produce the bacteriocin during the fermentation process.