Fresh bacterial and yeast inoculums were prepared from overnight cultures to obtain microbial inoculates in the logarithmic growth phase. The overnight culture of each microorganism was diluted to 1/100 in 10 ml MHB for bacteria or 10 ml SLM for the
yeast, and incubated for 4 to 6 h at 37 C for bacteria and 30 C for the yeast. Optical density was measured at 420 nm and appropriate dilutions were carried out following the standard growth curve to achieve a cell concentration of 105–106 CFU/ml as suggested by the Oxoid Manual (1995). Aliquots (100 ll) of the fresh inoculums were spread over the surface of MHA for bacteria and SDA for the yeast. Agar plates were incubated at 30 C for approximately 15 min until the microbial overlay had dried. Six susceptibility test discs (Oxoid, CT0998B, Ø = 6 mm) were placed onto the agar plates using a six cartridges disc dispenser (Oxoid, ST6090). Only one or two discs were used when essential oils showed great inhibition zones.