Starter Inoculum

Starting inoculum is used to help standardize initial growth of culture used in subsequent experiments. Starter culture can help you initiate a culture with a similar OD such that growth times and final OD achieved are similar throughout your experiments. If you are trying to achieve a precise initial OD for an experiment (e.g. minimum inhibitory testing), using a starter inoculum can help standardize experiments. 

Use a sterilized loophook, cooled after singing “row-row-row your boat” 2 x. Ensure that the shaft of the loop hook is cleaned. Starting with a streak plate, pull a well-defined colony roughly about a quarter the size of a hole punched circle. Add this to approximately 5 mL of liquid broth  in a culture tube by knocking the loop hook against the wall of the tube until the colony has come off of the end of the loop hook. Vortex the sample lightly and transfer the sample to a shaker. Make sure the cap allows for oxygen transfer but will retain sterility of the sample