Use of Bioprotective Potentials of Lactobacillus spp. for the Control of Post Harvest Rot of Sweet Potato (Ipomoea batatas (L.) Lam.)

Post-harvest losses of sweet potato (Ipomoea batatas (L.) Lam.) due to microbial spoilage remain a critical challenge in food security and agricultural sustainability, particularly in tropical regions. This study investigates the bioprotective potential of Lactobacillus species, specifically Lactobacillus plantarum and Lactobacillus acidophilus, in controlling fungal pathogens associated with the post-harvest rot of sweet potatoes. A total of 30 fungal isolates were obtained from infected sweet potato tubers and identified based on cultural and microscopic characteristics. Predominant fungi included Aspergillus niger, Aspergillus flavus, Fusarium oxysporum, Penicillium species, and Rhizopus stolonifer. In parallel, Lactobacillus species were isolated from fruit juices and screened for antifungal activity using in vitro dual culture assays. The results demonstrated significant inhibitory effects of LAB against the test fungi. L. plantarum exhibited the highest inhibition (45.00%) against F. oxysporum, while L. acidophilus achieved the greatest inhibition (40.16%) against R. stolonifer. Mean inhibition zones and radial growth measurements across multiple test fungi confirmed the strong antagonistic properties of these LAB strains. Notably, control treatments showed 100% radial growth of fungal colonies, emphasizing the efficacy of LAB as biocontrol agents. This study concludes that Lactobacillus species possess promising antifungal activity and can serve as eco-friendly alternatives to synthetic fungicides for the management of post-harvest diseases in sweet potato. The implementation of such biological control strategies could enhance food preservation, minimize economic losses, and promote sustainable agricultural practices.