Purpose: The objective of this work was to evaluate the antimicrobial activity of Cinnamomum cassia, Cinnamomum camphora and Litsea cubeba essential oils (EO) on planktonic and sessile Staphylococcus aureusGL 5674 cells, as well as to evaluate the action of the combination of these essential oils on biofilms formed by these bacterial strains on AISI 304 stainless steel, with a skim milk substrate.
Methods: To evaluate the antimicrobial activity of the EO, the MBC (minimum bactericidal concentration) of the EO tested on planktonic cells was determined, as well as the MBCB (biofilm minimum bactericidal concentration). In planktonic cells, the EO MBC was determined using the broth microdilution test in 96-well microdialysis plates. The final EO concentrations ranged from 0.078% to 10%. The bacterial culture was standardized in 108 CFU/mL. In sessile cells, biofilm was formed in microdialysis plate for 72 hrs at 37°C, and the EOs were tested in concentrations ranging from 0.078% to 10%, for 20 minutes. Sanitizing solutions based on the combinations of C. cassia, C. camphora e L. cubebaEOs were assessed on biofilms formed by GL 5674 strain in UHT skim milk after 72h of incubation.
Results: C. cassia, C. camphora e L. cubeba showed MBCs of 0.3125% ,1.25% and 0.63% respectively on GL 5674 planktonic cells. When in biofilm, this concentration was 4 times higher. The sanitizing solutions based on EOs were able to significantly reduce bacterial populations by 2.5 log CFU/cm2 (p<0,05) in relation to the control.
Significance: The combination of these EO presents promising results as sanitizers for use in the food industry.