Agar® McFarland Turbidity Standard
McFarland's turbidity standard are test tubes with standard dilutions that determine the turbidity of bacterial suspensions on the McFarland scale 0.5, 1, 2, 3, 4, used to standardize seed material.
APPOINTMENT
Standardization of the number of bacteria in bacterial suspensions.
SET COMPOSITION
McFarland standard 0.5 units – 1 test tube
McFarland's standard 1 unit - 1 test tube
McFarland standard 2 units – 1 test tube
McFarland's standard 3 units - 1 test tube
McFarland standard 4 units – 1 test tube
METHOD OF APPLICATION
Vortex or mix the standards by hand to obtain a homogeneous suspension. Prepare the inoculum required for testing using sterile saline. Compare the density of the obtained suspension with the density of the desired standard. Adjust the density of the suspension by adding saline if the suspension is more cloudy than the desired standard, or by adding culture otherwise.
The correspondence of the McFarland standards to the number of international turbidity units and the concentration of the suspension of bacteria of the intestinal group is shown in the table