This study was designed to assess the antimicrobial properties of the paired combinations of the
essential oils (EOs) of Cymbopogon citratus, Cymbopogon giganteus, and Lippia multiflora on Listeria
monocytogenes, Staphylococcus aureus, and Escherichia coli in roselle and tamarind drinks. The
chemical composition of the EOs was characterized by GC-MC and GC-FID. The microdilution and
checkerboard methods were used to assess antimicrobial activities and interactions of the EOs,
respectively. The three EOs mainly consisted of oxygenated monoterpenes followed by monoterpene
hydrocarbons. The three paired combinations of EOs exhibited synergetic effects against the
three bacteria strains in the tamarind water extract and against E. coli in the roselle water extract.
The combination of EOs decreased MIC values from 0.5 to 1333 folds. These results showed that
paired combinations of the EOs of this study can be used as preservatives in roselle and tamarind
water extracts.

Roselle; tamarind; essential oil; combination; antibacterial; synergistic effects