Lately, tomato (Lycopersicon esculentum Mill.) production has seen a global rise, driven by the crop’s economic value and nutritional benefits. This widely consumed vegetable-fruit is a key ingredient in cooking and juice production due to its rich content of vitamins and minerals. These advantages have spurred various research efforts aimed at enhancing different stages of its production. However, postharvest preservation remains a major challenge, particularly concerning health safety and product management. In many parts of Africa, large harvests often fail to generate significant profits as a result of postharvest losses. This study aimed to evaluate the potential of certain Lactic Acid Bacteria (LAB) supernatants in preserving fresh-cut tomatoes postharvest. A total of 250 LAB strains were isolated from 25 samples of locally fermented dairy products collected in Kuje, Abuja, Nigeria. Standard microbiological methods were employed to screen the isolates, with Lactobacillus plantarum (LB69) and Lactobacillus fermentum (LBB6) exhibiting strong in vitro antagonistic activity against Botrytis cinerea and Aspergillus niger, two fungi previously identified on decaying tomatoes. The LAB supernatants were subsequently applied in vivo to healthy tomato fruits, using sterile distilled water as a control. Results demonstrated a significant delay in fungal growth in treated samples compared to the control group. Specifically, L. plantarum (LB69) provided 53% and 42% protection against B. cinerea and A. niger, respectively, while L. fermentum (LBB6) achieved 41% and 33% protection. These findings suggest that LAB-based treatments hold promise for safer, more effective fungal disease control in tomato postharvest management.