Sterile technique is a set of principles and practices used by scientists to avoid unwanted introduction of microorganisms like bacteria or fungi into cell culture. When we culture tissues or cells, we don't want these microorganisms to destroy your cells. So we have a set of rules, quite strict rules, that need to be respected to minimize this risk of contamination. First we create a barrier between our skin and the things that we touch with gloves and with a lab coat. Then we use sterile solutions that usually come in bottles like cell culture medium or sterile equipment that has been through a sterilization process (like autoclaving). Then to keep this solution sterile we usually spray them with alcohol that can kill the micrograms that may be on the surface. We spray everything that enters the cell culture hood. Cell culture hoods are also called safety cabinets, and they help us to keep the cultures sterile. It uses air to kind of trap all the microorganisms and allow us to keep the cultures in sterile conditions, and it can be sterilized after use using UV light, just in case any microorganisms happen to get in despite all of our precautions. All of these different things are part of the practice of ‘sterile technique’ to allow us to do cell culture with minimal risk of contamination.