The solution of the tested compounds was prepared by the dilution method for the analysis, followed by the formation of series of 12 dilutions with liquid nutritious base. The 2.0 mL Casein Soya Bean digest broth was added to the 2.0 mL starting solution of test material and thus the first dilution was formed. Subsequently, 2.0 mL of this solution was diluted with 2.0 mL Casein Soya Bean digest broth to give the second dilution and so on until 12 dilutions were obtained