Effect of a Diffused Essential Oil Blend on Bacterial Bioaerosols

Chao, SC | Young, DG | Oberg, CJ

Journal of Essential Oil Research [J. Essent. Oil Res.]. Vol. 10, no. 5, pp. 517-523.
Sep-Oct 1998.

Thieves, a commercial blend of five essential oils, was tested for its antibacterial activity
against Micrococcus luteus, Pseudomonas aeruginosa and Staphylococcus aureus
bioaerosols. An aerosol suspension of each bacterial culture was sprayed into a 0.4 m
super(3) enclosed fume hood previously sterilized by ultraviolet light. Thieves essential
oil blend was then diffused into the hood for a given time. Depositional sampling results
showed a significant reduction (P<0.0001) in the aerosol-borne bacterial load after
diffusion of the oil blend. Controls showed no inhibitory effect of oil that may have
settled on the exposed plate surfaces during bacterial depositional sampling. Inhibition
levels appear to be organism specific. There was an 82% reduction in M. luteus
bioaerosol, a 96% reduction in the P. aeruginosa bioaerosol, and a 44% reduction in the
S. aureus bioaerosol following 10 min of exposure. Results for the time exposure
threshold of diffused oil showed that after only six min a 90% reduction in M. luteus
viability occurred. Diffusion of the oil blend, Thieves, can significantly reduce the
number of aerosol-borne bacteria and may have application in treating air for enclosed
environments and preventing transmission of aerosol-borne bacterial pathogens.