Antibacterial activity of candles

University of Southampton, UK - Apr 26, 2006

Interaction of air ions and bactericidal vapours to control microorganisms’
Gaunt, L. F., Hughes, J. F. and Higgins, S. C. (2005) Interaction of air ions and bactericidal vapours to control microorganisms’. Journal of Applied Microbiology 99 pp. 1324-1329.
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Abstract
Aims: The aim of this study was to investigate the antibacterial activity of candles containing specific antibacterial compounds, such as essential oils and their constituent compounds. The importance of the ionization products from the flame and the aerial concentration of the volatile compounds were investigated.
Methods and Results: Agar plates inoculated with Escherichia coli (DH5) (E. coli) or Staphylococcus aureus (NCTC strain number 8532) (S. aureus) were exposed in a large air-tight chamber to candle flames combined with the volatile bactericidal compounds β-pinene and orange oil. A steady decline in E. coli numbers was observed over time due to the effect of a candle flame. This was significantly increased by the addition of volatile oils. The number of S. aureus colonies was not reduced by a plain candle, but significant reductions were caused following exposure to β-pinene and orange oil candles. As aerial concentration of the volatiles was increased the viability of E. coli and S. aureus declined. Ionization products from the flame made a significant contribution to the observed effects, as intercepting the ions on a grounded grid over the agar plates allowed at least 20% more cells to survive.
Conclusions: This study demonstrates the antibacterial properties of ionization products from a candle flame, and that this effect can be significantly increased by the addition of specific antibacterial compounds, such as orange oil and β-pinene. The role of both the ionization products from the candle flame and the concentration of volatiles released are important to the effect.
Significance and impact: The technique described here offers a new and novel technique for reducing the concentration of bacteria on surfaces.

Item Type Article
Keywords Flame, ionization, essential oil, volatile, antibacterial
Research Group Electrical Power Engineering
BIO@ECS Research Group
Deposited On 26 April 2006 by Gaunt, Lindsey
Alternative Locations http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1365-2672.2005.02729.x
ISSN 1364-5072
ID Code 12398
Performance Indicator EZ~03~02~11
Authors
LF Gaunt
JF Hughes
SC Higgins
Editors
A Gilmour