McFarland (0.5 Turbidity Standard) Preparation

A 0.5 McFarland turbidity standard was prepared for the standardization of selected test organisms that are needed for the determination of the minimum inhibitory and bactericidal concentration, for performing the agar diffusion test, and other tests necessary for the study such as biochemical tests. This 0.5 McFarland turbidity standard was prepared into a test tube from the mixture of barium chloride dehydrate (BaCl2. 2H2 0) solution and sulfuric acid (H2 SO4) with verification of the mixture absorbance (0.08–0.10) density precision via a spectrophotometer at a wavelength of 625nm. The prepared tube was stored in a sealed container at room temperature in a dark place.¹³