Isolation and Optimization of Bacteriocin-Producing Lactic Acid Bacteria from Nigerian Fermented Foods

<ns3:p> The increasing need for natural and safe food preservatives has triggered interest in bacteriocins (antimicrobial peptides) produced by lactic acid bacteria (LAB) as viable alternatives to chemical preservatives. This study aimed to optimize bacteriocin production from LAB isolated from Nigerian fermented foods and to evaluate its effectiveness in extending the shelf life of selected fruit juices. A total of 33 LAB strains were isolated from Nigerian local fermented foods (iru, fufu, and ogi) using MRS agar, screened for antibacterial activity against selected foodborne pathogens, and characterized using 16S rRNA sequencing. Five LAB strains were identified: <ns3:italic>Lactobacillus plantarum</ns3:italic> (PV937062, PV937063, PV937065), <ns3:italic>Lactobacillus paracasei</ns3:italic> (PV937064), and <ns3:italic>Lactobacillus acidophilus</ns3:italic> (PV937061). The agar well diffusion method was used to optimize the effects of culture age, pH, temperature, organic solvents, ultraviolet radiation, protease treatment, and storage conditions on the bacteriocin activity. This study demonstrated that optimized bacteriocins by LAB from Nigerian fermented food has the potential to be an effective food preservative by extending the shelf life of fruit juices as a safe and environmentally friendly alternative to synthetic preservatives to enhance food safety and quality. </ns3:p>