Sterilization Validation via Dual Contamination Cycles
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Solution Overview
Problem
Current methods for validating sterilization processes, especially for products and containers that can be opened and resealed, face challenges in achieving a sterility assurance level (SAL) of 10−6 due to difficulties in extrapolating decay curves for low contamination levels and inconsistent sterilization across categories, leading to uncertainties in decontamination effectiveness.
Innovation Solution
A method involving two sterilization cycles with initial contamination of at least 105 living microorganism cells, followed by verification of sterility after each cycle, ensures a reduction of at least 10 logs of contamination, using biological indicators to demonstrate the destruction of microorganisms, and an installation with a workstation for rapid opening, re-contamination, and re-closure to optimize the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single contamination step with more than 10^5 living microorganism cells is performed followed by one sterilization cycle, then the sterilization process can be validated, but the sterility assurance level SAL of 10^-6 cannot be reliably achieved due to difficulties in extrapolating decay curves for low contamination levels
Solution Approach 1:
The validation process is divided into two separate sterilization cycles with contamination steps in between. The first sterilization cycle reduces contamination from more than 10^5 cells to more than 10^3 cells, then a second contamination step introduces more than 10^5 cells again, followed by a second sterilization cycle that achieves complete sterility. This segmentation allows validation at measurable contamination levels while ensuring the required SAL of 10^-6.
Solution Approach 2:
The first sterilization cycle is performed as a preliminary action to reduce the initial high contamination level to a lower but still measurable level (more than 10^3 cells). This preliminary reduction allows for better measurement and control before the final sterilization cycle, avoiding the need to directly measure and extrapolate from extremely low contamination levels.
2Adaptability or versatility
If sterilization processes are divided into two categories with different validation methods, then each category can be addressed with appropriate techniques, but consistency and reliability across different sterilization processes cannot be ensured
Solution Approach 1:
The two-cycle validation method with intermediate contamination is designed to be universally applicable to all sterilization processes regardless of category. Whether the process follows exponential decay (first category) or does not (second category), the same validation approach using biological indicators and the two-cycle procedure ensures consistent and reliable validation across different sterilization technologies.
3Reliability
If biological indicators are used to assess sterility assurance level, then the destruction of microorganisms can be demonstrated, but the probability of non-sterility cannot be accurately assessed when decay curves cannot be established
Solution Approach 1:
The validation is segmented into two phases: the first sterilization cycle demonstrates reduction of microorganisms from more than 10^5 to more than 10^3 cells, and the second sterilization cycle demonstrates complete destruction achieving sterility. This segmentation allows biological indicators to effectively demonstrate microorganism destruction at each stage without requiring accurate probability assessment at extremely low contamination levels.
Data Source
AI summary
A method for validating a method for sterilizing an item, making it possible to validate the sterility assurance level achieved with this sterilization method. The method includes carrying out a first step of contaminating a container receiving the item with more than 105 living microorganism cells, then carrying out a first sterilization cycle with the chosen method, then opening the container in order to contaminate it again with more than 105 living microorganism cells, then carrying out a second sterilization cycle with the same method, and finally checking the sterility of the container after the first sterilization cycle and after the second sterilization cycle. The method is applicable in particular for products and devices intended for health use.