Bacteriocins are natural antimicrobial peptides primarily produced by lactic acid bacteria (LAB). This study focused on isolating, characterizing, and optimizing bacteriocins from LAB recovered from traditionally fermented Nigerian foods to explore their potential in food preservation. A total of fifty LAB isolates were obtained from ten food samples: Kunun-zaki, Kunun-aya, Wara, Nono, and Daddawa. Isolation was performed by anaerobic culturing on de Man, Rogosa, and Sharpe (MRS) agar at 37°C for 72 hours, followed by morphological and biochemical characterization and confirmation through 16S rRNA gene sequencing. The LAB isolates obtained were Lactococcus lactis subsp. hordniae (86.61% identity), Lactococcus garvieae (96.61%), Lactococcus lactis strain CAU3142, and Lactococcus garvieae CAU9944. The bacteriocins produced by LAB isolates exhibited significant strain-dependent antibacterial activity against food spoilage bacteria namely; Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Toxicological evaluation of the probiotics in albino rats at doses up to 5000 mg/kg revealed no mortality or significant adverse effects. When applied at 10% and 15% concentrations, these bacteriocins significantly suppressed microbial load, effectively extending shelf life compared to controls, which showed progressive spoilage. Additionally, bacteriocin treatments improved proximate nutritional profiles including protein, ash, and carbohydrate contents, and enhanced sensory properties and overall acceptability. The bacteriocins exhibit strong antimicrobial activity, safety, and the capacity to extend shelf life while improving the nutritional and sensory qualities of Masa and Akamu. These findings support their promising application as natural, sustainable food preservatives in Nigeria and beyond.