Out of curiosity i wanted to ask what dilution base did you use for the orange essential oil? And why did you choose such strain no of E.coli and Pseudomonas? Also what conditions are you maintaining for them to grow? Did you place the discs in a sterile zone between flames or a HEPA filtered zone?No where i can see that your plates are sealed with paraffin coat .How do you keep it in sterile zone? What Biosafety Level do you maintain in your lab ?