INVITRO EVALUATION OF LACTOBACILLUS ACIDOPHILUS FOR ANTIFUNGAL ACTIVITY AND ITS IMPACT ON MAIZE NUTRITIONAL QUALITY

Background: Fungal contamination of food commodities is a persistent global concern, leading to spoilage, discoloration, nutrient degradation, and the production of toxic metabolites that pose serious risks to animal and human health. Among phytopathogenic fungi, Aspergillus flavus is particularly problematic due to its ability to colonize cereal grains and compromise both food safety and nutritional quality. In recent years, lactic acid bacteria have gained attention as eco-friendly alternatives to chemical preservatives because of their antimicrobial properties and their role in improving food quality and stability. Objective: This study aimed to evaluate the antifungal and bioprotective potential of Lactobacillus acidophilus against Aspergillus flavus and to assess its impact on the nutritional and antioxidant profile of maize (Zea mays L.) grains. Methods: The antifungal activity of L. acidophilus against A. flavus was assessed using an agar well diffusion assay. A bioprotection experiment was performed in which maize grains were treated with L. acidophilus culture and subsequently inoculated with A. flavus, followed by a 10-day observation period. Proximate analysis of maize grains was conducted to determine moisture, protein, fat, fiber, and ash contents. Total phenolic and flavonoid contents were quantified using spectrophotometric methods. All experiments were performed in triplicate and statistically analyzed. Results: Lactobacillus acidophilus produced a clear inhibition zone of 30.54 ± 0.32 mm against A. flavus, while no inhibition was observed in the control. In the bioprotection assay, complete suppression of fungal growth was observed on treated maize grains after 10 days, whereas control grains showed visible fungal colonization. Proximate analysis revealed reduced moisture content (20.44 ± 0.45%) and increased protein (8.54 ± 0.87%), fat (2.54 ± 0.65%), fiber (16.87 ± 0.32%), and ash (12.54 ± 0.55%) contents in treated grains compared with controls. Total phenolic content increased to 100.65 mg GAE/g and flavonoid content to 93.44 mg quercetin equivalents/g following bacterial treatment. Conclusion: The findings demonstrated that Lactobacillus acidophilus is an effective bioprotective agent against Aspergillus flavus, while simultaneously enhancing the nutritional and antioxidant quality of maize grains. This study highlights the promising application of probiotic-based biotechnology as a safe and sustainable strategy for improving cereal grain safety and value.