ANTIMICROBIAL RESISTANCE MODULATION OF MILK STAPHYLOCOCCUS AUREUS USING LEMONGRASS ESSENTIAL OIL NANO EMULSION

Abstract

Introduction: Essential oils exhibit potent antimicrobial properties, offering natural and effective solutions for combating a wide range of pathogens.

Objective: In this study, Lemongrass (Cymbopogon citratus) Nano emulsion was prepared using Tween80 aqueous solution as the surfactant and various core materials, including pure canola oil and a mixture of lemongrass oil (LG) and canola oil (CA) at different ratios.

Materials and Methods: Bacterial isolation from cow milk samples was performed using Mannitol Salt Agar (MSA) followed by incubation for 24 hours. The GC-MS analysis was conducted to determine the chemical composition of the sample. Nano emulsions were characterized by particle size and turbidity.

Results: The GC-MS analysis revealed citral (geranial) as the dominant compound (32.4%), followed by neral (31.41%). Nano emulsion particle sizes decreased with increasing concentration, ranging from 31.99 nm (1% w/v) to 40.3 nm (2.5% w/v). Turbidity analysis showed an absorbance value of 0.128 ± 0.05 at 600 nm. In cow milk, the Nano emulsion demonstrated a dose-dependent reduction in microbial count (from 10⁸ CFU/mL in control to 10² CFU/mL at 400 ppm/2 mL). The minimum inhibitory concentration (MIC) of 400 ppm against Staphylococcus aureus confirmed its antimicrobial efficacy. Time-kill dynamics further supported dose-dependent bacterial inhibition.

Conclusion: These findings highlight lemongrass essential oil's significant antimicrobial properties, suggesting its potential applications in food preservation and pharmaceutical industries.