In a separate research, the micro-atmosphere method was used to investigate the anti-fungal efficacy of the essential oils from the cinnamon, a plant belonging to the genus Cinnamomum.
The procedure was employed to ensure that the active films, the material containing the active compound, does not come into direct contact to the tested fungal suspension.
The micro-atmosphere method was performed, in order to evaluate the indirect effects of active films against P. digitatum. Addition of 0.5% cinnamon essential oil, led to 12% inhibition of fungal growth. Higher anti-fungal effects were obtained by adding higher amounts of the essential oil. An inhibition of fungal growth between 28% and 50% were observed for the films incorporated with 1.5% and 3% essential oil, respectively.
In this particular research, the potential anti-fungal agent was subjected to both disk diffusion test and the micro-atmosphere method for comparison and to get an idea of how the active compound may be utilized. The active compound exhibited higher anti-fungal effects in the disc diffusion test compared to the micro-atmosphere assays. This could be attributed to the fact that in the disc diffusion test, both direct contact and migration of active compounds from the film to the outside induced the observed antimicrobial effects. On the other hand, only the migration of the volatile compounds to the headspace, may cause the anti-fungal effect in the micro-atmosphere method.