Development of surfactin based nanoemulsion formulation from selected cooking oils: Evaluation for antimicrobial activity against selected food associated microorganisms

Selected cooking oils such as sunflower, castor, coconut, groundnut, and sesame oils were screened for the development of a surfactin based nanoemulsion formulation. Mean droplet size of different surfactin based cooking oil emulsions varied from 72.52 to 875.22 nm with the least size recorded by sunflower oil based nanoemulsion formulation. On further screening for antibacterial activity sunflower oil-based nanoemulsion designated as AUSN-1 showed highest activity against Salmonella typhi, followed by Listeria monocytogenes, and Staphylococcus aureus. AUSN-1 also demonstrated a high fungicidal activity against Rhizopus nigricans, followed by Aspergillus niger and Penicillium sp. and a greater sporicidal activity against Bacillus cereus and Bacillus circulans. In situ evaluation of AUSN-1 for antimicrobial activity on food products such as raw chicken, apple juice, milk and mixed vegetable showed a significant reduction in the native cultivable bacterial and fungal populations of these products.

► Cooking oils were screened to develop a surfactin based nanoemulsion formulation.
► Sunflower oil nanoemulsion (AUSN-1) recorded the least mean droplet size.
► AUSN-1 showed highest activity against Salmonella typhi, and Listeria monocytogenes.
► A higher sporicidal and fungicidal activity was exhibited by AUSN-1.
► Reduction in microbial populations was observed in AUSN-4 treated food samples.