Quantification of bacterial load: Inoculating the bacterial samples on agar plates

You and Sam label agar plates carefully with the sample name and dilution on the bottom of the petri dish, rather than on the lid, to ensure that even if a lid is misplaced, the identification of the sample is not compromised. 

You and Sam inoculate plates by transferring 100 μL of each diluted sample onto an LB agar plate. A sterile loop is used to distribute the sample evenly across the surface of the agar, using the spread plate technique, as shown below. You close the agar plates and invert them (lid side down) to prevent condensation from disrupting microbial growth on the agar surface. The plates are incubated overnight at 37 °C.

Website: https://microbeonline.com/spread-plate-technique/