There are multiple Biological Indicators that can be used in Sterilisation Monitoring. Each individual indicator uses bacterial spores of known sterilisation procedure resistance. 

Spores are inoculated on a carrier such as plastic, glass or filter paper and situated within an additional packaging that allows for the prevention of damage or contamination, while simultaneously allowing the sterilant to come in contact with the test organisms. It is essential to utilise an aseptic technique when transferring any inoculated carriers to the growth medium. This prevents accidental contamination. 

Self-Contained Indicators comprise of an ampule of growth medium as well as an inoculated carrier with the required population of test organisms. This form of Biological Indicator and carrier provide sterilisation resistance. This resistance depends on the length of time the sterilant takes to penetrate the surface. Smooth penetration is controlled by composition and design at the manufacturing level. The sample is ready for incubating following the sterilisation process. 

Spore suspensions are another type of biological indicator that can directly be applied to the surface that will undergo the sterilisation procedure. Simulations of inoculated products are generally a requirement in order for the final product to show.