 It is preferable to make 10 fold serial dilution of the bacterial culture inside safety cabinet for void contamination. For making serial dilutions, you would require bacterial growth sample, pipette tips, glass tubes, bacterial culture plates and sterile disposable bacterial spreader. In the first step, use the pipette to pick 1 ml of bacterial sample and add into the glass tube containing 0.9% sterile saline solution to make the first dilution. Discard the pipette tip and tightly close the glass tube to mix the content. After mixing, put the glass tube back into the rack and loosen the caps of the remaining glass tubes containing 0.9% sterile saline solution to make further dilutions. Now pick 1 ml solution from the first bacterial dilution and add it to the second glass tube with the saline solution to make second dilution. Close the cap tightly and discard pipette tip, now mix the content. For making third dilution, 1 ml solution is picked from second dilution and add it to the third glass tube. Discard the pipette tip and close the glass tube with the cap and mix the contents. Add the necessary details regarding the dilution factors onto the petri plate. Now invert the culture media petri plates and place them in front of the other dilutions. By using the pipette, pick some solution from the first dilution glass tube and add it into the first culture media petri plate. Discard the pipette tip. Pick solution from the third dilution test tube and add it into the third culture media petri plate. Discard the pipette tip. Take the disposable bacterial spreader and use it to gently spread the first dilution in the culture media plate. Move the spreader throughout the plate to uniformly spread the solution inside the plate. To use, discard the bacterial spreader. Take out another bacterial spreader and repeat the spreading procedure for the second dilution in the culture medium. Make sure to cover the corners of the culture media petri plate as well. Add the spreader. Again take out a new bacterial spreader and spread the third dilution in the third culture media petri plate until the solution is uniformly spread throughout the plate. Discard the bacterial spreader. Now invert all the culture media petri plates for incubation. Next place the culture media petri plates into the incubator at 37 degrees celsius. For 12-24 hours of incubation take out the petri plates to check bacterial growth. This is a colony counter which is used to count the number of colonies on a solid culture medium. The petri dish is placed on the plate holder and gentle force is applied on the petri plate while looking at the colonies through the lens. A number is displayed digitally as you keep on counting the bacterial colonies as demonstrated. After counting the number of colonies it can be used to save the counting number for a maximum of three different plates.