Microbiologists and students of microbiology may use an aseptic technique to attempt to keep specimens of microorganisms free of microbial contamination. People may commonly use the aseptic technique when transferring bacteria from one test tube or flask to another. Such a procedure, using a flame sterilization method, might occur as follows.
- A person would assemble the closed tube or flask from which, and the closed tube or flask to which the specimen is to be transferred, an innoculating loop , and a fire source, all on a clean, preferably microbe-free surface with some overhead protection from airborne microbes.
- The person would start the fire, and move the end of the innoculating loop, in a slow back-and-forth motion, through the top of the blue part of the flame. The person would not allow the loop to touch anything except the specimen itself, until the entire procedure is finished.
- Preparing to execute the specimen transfer, the person would hold both of the tubes or flasks in one hand, probably the opposite of the writing hand. The person would then open the tube or flask containing the specimen source and briefly hold the top of it in the flame, to kill unwanted microbes.
- Quickly, so as to minimize the possible time for contamination of the specimen in the source tube or flask, the person would use the innoculating loop with their writing hand to retrieve the specimen, and then sterilize the top of the tube or flask again before immediately closing it.
- Keeping in mind that the specimen on the innoculating loop could be contaminated during every unit of time it is exposed, the person would repeat the previous step identically with the tube or flask in which the specimen is to be deposited; however, the person would be depositing the sample into the tube or flask.