ASHS 2025 Conference

Ensuring food safety and extending shelf life remain key challenges in post-harvest management of fresh produce. This study investigates the potential of postbiotic biopolymers, specifically Lactobacillus-derived exopolysaccharide (EPS), as a natural and sustainable emulsifier for stabilizing the bioactive antimicrobial volatiles limonene, and eugenol in oil-in-water nanoemulsions. The developed EPS-based nanoemulsion exhibited strong antimicrobial activity against Escherichia coli, Listeria monocytogenes, and Salmonella Poona, achieving >3.0 log reductions on fresh lettuce through immersion and spray applications, while preserving sensory attributes such as texture, color, and taste. Additionally, the nanoemulsion demonstrated a bacteriostatic effect, achieving up to a 3.17 log CFU/cm² biofilm reduction on stainless steel and plastic surfaces (p < 0.05), and a 3-log reduction of Salmonella and E. coli on tomato and blueberry fruit surfaces, along with a 4-log reduction of L. monocytogenes on the soft cheese queso fresco. Stability assessments confirmed that the emulsions remained highly effective across diverse environmental conditions, including temperatures of −20 to 70°C, pH 2–9, and salinity levels from 1%–30%, making them well-suited for real-world agricultural and food processing applications. The synergistic action of EPS and bioactive volatiles not only prolonged shelf life and reduced microbial colonization but also provided a non-toxic, biodegradable alternative to synthetic preservatives, addressing sustainability concerns in food safety and post-harvest preservation. These findings highlight EPS-based nanoemulsions as a promising alternative for enhancing food safety, reducing microbial risks, and supporting sustainable post-harvest practices across fresh produce, dairy, and food-contact surfaces. This work was supported by USDA-NIFA-2024-51181-43464 through the Vegetable and Fruit Improvement Center of Texas A