Amit Kumar Tyagi, Anushree Malik

Applied Microbiology Laboratory, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi 110 016, India.

Abstract

The antimicrobial activity of Eucalyptusglobulus essential oil was evaluated against 14 food spoilage microorganisms in liquid and vapour phase using agar dilution/well diffusion method and disc volatilisation method, respectively. The minimum inhibitory concentration (MIC) varied from 2.25 to 9 mg/ml for bacterial and fungal strains, and from 1.13 to 2.25 mg/ml for yeast strains. Significantly higher antimicrobial activity was observed in the vapour phase. The chemical composition of E. globulus in liquid as well as in the vapour phase was determined by gas chromatography (GC), gas chromatography/mass spectrometry (GC-MS) and solid phase micro extraction-gas chromatography mass spectrometry (SPME GC-MS), respectively. The dominant compounds in E. globulus oil were 1,8-cineole (45.4%), limonene (17.8%), p-cymene (9.5%), γ-terpinene (8.8%), α-pinene (4.2%) and α-terpineol (3.4%), while in the vapour, 1,8-cineole (34.6%), limonene (29.9%), p-cymene (10.5%), γ-terpinene (7.4%), α-pinene (4.0%) and α-phellandrene (2.4%) were identified.