Utilizing of Nonstarter Lactic Acid Bacteria as Bio-Preservative Agents to Inhibit Microbial Contamination and Extend Yogurt's Shelf Life.

Fungal spoilage significantly affects the quality of dairy products, causing economic losses and health risks due to mycotoxin production. While physical and chemical methods are commonly used to control spoilage, chemical additives may threaten consumer food safety. Due to their antimicrobial properties, lactic acid bacteria like Lactobacillus plantarum and Lactobacillus rhamnosus are promising natural preservatives. This study evaluated the efficacy of these two bacteria to prevent mold spoilage and extend the shelf life of yogurt. Results showed that yogurt samples containing these protective cultures were resistant to mold spoilage, increasing shelf life from 21 to 43 days compared to controls. The pH levels and sensory characteristics showed no significant differences between treated and control samples. Additionally, fermentation time was reduced by 15 min in the treated samples. The strongest inhibition of Geotrichum mold growth was observed with Lactobacillus plantarum, showing an average inhibition zone diameter of 27 mm, while Lactobacillus rhamnosus exhibited a 23 mm zone. These findings highlight the potential of these bacteria as natural preservatives in the dairy industry. Furthermore, molecular docking simulations were conducted to elucidate the interactions between microbial metabolites and spoilage-related enzymes, providing mechanistic insights into their antimicrobial action.