An important specification that has to be stated by the manufacturer of biological indicators is their population or viable spore count.
Depending on the employed sterilization method, the required minimum population of biological indicators for monitoring can vary. As transport and storage conditions as well as ageing can influence the population of the biological indicator it is advisable for users to check this specification. For users complying with USP this a requirement.
We determine the population according to ISO 11138-1 and USP.