Biological indicators and monitoring systems for validation and cycle control of sterilization processes.

The article is divided in four parts. The first part deals with terms and definitions. After that there is given a description of the most common types of biological indicators. These two parts furnish material and introduce to the third part, a survey of the components of monitors, their functions and the criteria one has to take into consideration when designing them. The fourth and last part deals with the most essential feature of biological indicators, the resistance, its calibration, description and adjustment.