Antimicrobial activity of the combination of red galangal (Alpinia purpurata K. Schum) and cinnamon (Cinnamomum burmanii) essential oils on Escherichia coli and Staphylococcus aureus bacteria

Abstract

Essential oils from spices such as red galangal and cinnamon are known to have antimicrobial activity that is strong enough against pathogenic and food destroying bacteria, so it has the potential to be developed as a preservative, especially in food. High antimicrobial activity is generally obtained at high concentrations, which can affect sensory acceptance when applied to food. One way to overcome this problem is to combine the use of essential oils. This study aims to determine the effect of the ratio of the combination of red galangal and cinnamon essential oils to its antimicrobial activity on Escherichia coli and Staphylococcus aureus bacteria. The research was carried out with an experimental method which was analyzed descriptively. Antimicrobial activity testing was carried out by the agar diffusion method and contact method to determine the inhibition growth of E. coli and S. aureus bacteria. The treatment consists of 5 ratios combination of red galangal and cinnamon essential oils, which were 1:0, 0:1, 1:1, 1:2, and 2:1 (v/v). The results showed that the ratio of the combination of red galangal and cinnamon essential oils showed a strong effect on antimicrobial activity towards E. coli and S. aureus. The combination of essential oil at 1:1 (v/v) ratio showed the highest antimicrobial activity against E.coli which was 20.5 mm of inhibition zone, while toward S. aureus was 21.25 mm inhibition zone (strong activity); and could reduce the total test bacteria by reducing 16.85% of E. coli and 21.69% of S. aureus bacteria after 24-hour length incubation.