So can Eucalyptus oil be used in food?

There would likely be few Australian homes that do not have a small bottle of Eucalytus oil in their bathrooms. It has long been know that this, and other essential oils, has antibacterial properties and is great for applying to cuts and other simple skin abrasions.

A recent study, Chemical composition and antimicrobial effects of essential Oils of Eucalyptus globulus, Myrtus communis and Satureja hortensis against Escherichia coli O157:H7 and Staphylococcus aureus in minced beef, has shown that essential oils also seem to have great antimicrobial properties in food as well.

The oils were extracted from leaf parts to ensure they were pure and analysed by gas chromatography/mass spectrometry to determine the main components. They were added into fresh minced beef at a level between 0.1 and 0.44% using the agar diffusion technique.

The meat was then inoculated with both Staphylococcus aureus CECT 4459 and Escherichia coli O157:H7 CECT 4267 at a level of 5 × 105 colony forming units (cfu)/g and stored at 5 ± 2 °C.

The results show that the Eucalyptus and Satureja oils had excellent antimicrobial properties against both the E.coli and S.aureus with up to a 70.74% reduction after seven days.

A taste panel was also done to test whether there were any organoleptic issues with the essential oils at those levels. It was found that the aroma levels were acceptable.

At this stage these essential oils are not permitted to be added to foods in Australia, but this study and others in the future may open up this as an alternative method of preserving food, and particularly meats.

The study was by D. Djenane ,T. Amrouche, S. Boubrit, N. Boussad (Faculté des Sciences Biologiques et des Sciences Agronomiques. Dept. Biochimie et Microbiologie) and J. Yangüela , P. Roncalés (Departamento Producción Animal y Ciencia de los Alimentos. Facultad de Veterinaria. Universidad de Zaragoza).

It was first published online at Food Science and Technology International on 02/11/11.