The Negative Control is a media ampoule made from the same lot of media used to make the corresponding spore ampoules. Negative Controls can be utilized in one of two different ways:
- The negative control can follow the spore ampoule through the process. In this way it can be used to verify that any color change seen immediately upon removal from the process was a result of the process and not due to spore germination or growth.
- The negative control can be incubated (not having gone through the process) along with the positive control (an unexposed to sterilant spore ampoule) and test spore ampoules. This illustrates that the media is sterile and can be used to compare against the positive control for color reference.