Sterilization is a top priority in any science or medical lab, including a microbiology lab. Sterilizing instruments, or parts of instruments, requires time and heat. Heat is usually supplied by a Bunsen burner in the lab or classroom; this produces additional problems such as the use of open flame, particularly when students are new to the lab and safety methods. Additionally, one Bunsen burner is never enough, and running multiple burners produces heat that changes the room temperature of the lab -- which is a problem for some materials. The use of applicator sticks is relatively inexpensive and the applicator sticks are disposable, so no need to run Bunsen burners in mass sterilization efforts.
Each student or lab technician may easily have his own supply of wooden applicator sticks, which are kept in a sterile test tube with a stainless steel cap on the end. The sticks do not need sterilization as other instruments would, but the test tubes should be sterilized before adding the sticks and students should be instructed to avoid contaminating the sticks. This includes not using the mouth or fingernails to open the test tube or withdraw the sticks, only touching one end of the applicator stick and using new sticks for each new material or task.
Applicator sticks are commonly employed when the need to mix small amounts of materials arises. The materials are combined in a small test tube, dish or other sterile container using a fresh applicator stick. The final applicator stick used with the mixing materials may be used for stirring the mixture, or a fresh applicator stick may be used instead. When finished, the applicator sticks are properly disposed of to avoid accidental contamination of laboratory surfaces, notebooks, pens, clothing and classmates. A pipette would not be used to mix materials.
Transferring a material requires a fresh applicator stick each time. The applicator stick must touch the main container of the material, remove a small amount of that material and then deposit it in a dish, slide or test tube. Other materials already in that destination may contact the applicator stick so if more of the material is needed, use a fresh applicator stick and dispose of the used one. This reduces the risk of accidentally contaminating an entire container of a given material which can, as microbiology students learn, become dangerous if the mixture results in a hazardous product.