Streak Plate

Do in a sterile environment

You will need:

• A loop hook
• Wooden stab (sterile)
• Agar media
• Freezer stock

A streak plate is an agar pate that with distinct single colonies grown such that any further culture taken from one of these colonies can be assumed to be from an genetically identical bacterium. It allows continuity between experiments. A streak plate is struck from a freezer stock, stored either at -80 ˚C or in liquid nitrogen. Understand your specific strand.

A small ~ 10 uL spot of freezer stock is transferred to an agar plate prepared with the appropriate medium (e.g., Lysogeny Broth (LB), Minimal Davis (MD)). This might be done with a wooden stick, a sterile clean pipette tip, or a cool sterile loop hook. Be sure to do this quickly as having freezer stocks prolonged for more than several minutes can significantly decrease their viability.

Note: be careful when you are taking freezer stock. Freezer stocks must be kept pure to ensure the validity of experiments.

Once the spot has been added to the specific agar media, return the freezer stock. Using a loop hook spread the freezer stock spot on the plate near the edge first, flip your loop hook and then streak a large zig-zag pattern pulling once through the dense culture. Flame your loop and then repeat this process 2 more times. The effect should be a thinned stock capable of producing single colonies.

https://microbeonline.com/streak-plate-method-principle-purpose-procedure-results/