ABSTRACT

According to the literature, lactic acid bacteria (LAB) have been used for ages as a natural preservative for dairy products as well as protective cultures. This is mainly due to their production of antimicrobial substances like organic acids and bacteriocins and their ability to compete against pathogenic and spoilage bacteria for nutrients. Nunu is a fermented dairy product enjoyed by the people of West Africa. This work was carried out for the purpose of determining and recording the bacteriocin produced by the LAB Isolate when supplemented with some carbon sources, nitrogen sources, potassium sources, magnesium salts and surfactants and identifying the antagonistic effects of bacteriocin of the bacteria Lactobacillus plantaruni against some pathogenic/spoilage organisms which include Escherichia co/i and Staphylococcus aureus. However, in this study, the bacteriocin of the LAB were effective against Gram negative bacteria including E. co/i and Staphylococcus aureus which is gram positive. According to the present study, the media supplemented with glucose gave the highest mean zone of inhibition on Escherichia co/i of 17.6mm while urea gave the highest mean zone of inhibition on Staphylococcus aureus of 11 .2mm. For the two tests organisms, the surfactant, glycerol, produced the lowest mean zone of inhibition of 2.0mm respectively. Bacteriocin is an antimicrobial that inhibits the growth of some pathogenic microorganisms especially in food, and it should be adopted as it has low health risk.