The microbial community, microflora or biofilm is a living entity. This means that it changes continuously depending on circumstances (moisture, nutrition, temperature…). Despite these changes the goal of the microbial community is to stay alive as long as possible. Micro-organisms can do this by adapting themselves to the circumstances and by communicating with each other (this is called quorum sensing). In order to create and preserve a healthy microflora, good micro-organisms, also called probiotics, are used.