Environmental Monitoring vs. Sterilization Validation
What is environmental monitoring?
Environmental monitoring is the tools and techniques used to observe an environment, characterize an environment’s quality, and ensure that an environment meets established acceptance criteria.
What is sterilization?
Sterilization is any process that removes, kills, or deactivates all forms of life. Sterilization is related to the term sterile, which means a complete absence of viable microorganisms or microbes that have the potential to reproduce. Thus, sterile products that undergo sterilization are often chemically or heat sterilized after being placed in their final packaging. The chemical or heat sterilization kills any microorganisms inside the products (obtained during manufacturing and packaging). This chemical or heat sterilization process after final product packaging is known as terminal sterilization.
What is the difference between sterile and aseptic?
While both sterile and aseptic products will prevent microbial contamination following use, the processes by which microbial contamination is prevented are different. An aseptic process prevents contamination by the exclusion of microorganisms. In contrast, products created using a sterile method use a terminal sterilization process to kill live microbes before product use. Though the definitions for aseptic and sterile are not the same, sterile is used interchangeably with aseptic. Indeed, many products labeled as sterile are manufactured by aseptic processing rather than terminal sterilization.
How do environmental monitoring and sterilization relate?
Sterilization refers to removing, killing, or deactivating live microbes from a product, surface, piece of equipment, or environment. The reason that viable (living) microorganisms alone are of concern for sterilization is that only live microorganisms have the potential to reproduce, whether in the human body, on a surface, on the product, or within the product itself.
Environmental monitoring for medical products and medical devices controls the microbial acceptance criteria for the manufacturing environments throughout the entire lifecycle of the product, from raw materials to end-use or expiration. The sterility of manufacturing equipment, raw materials, work surfaces, transfer lines, etc., is critical to keeping a cleanroom or aseptic manufacturing environment free from microbial contamination. Sterilization processes support keeping these components of the manufacturing environment sterile.
What are the differences between environmental monitoring and sterility testing?
The most popular method for sterilization validation is an overkill method. Overkill methods are used to verify that a certain sterilization process can achieve a certain level of sterility even if the bioburden is higher than expected, in a difficult to sterilize location, or the sterilization cycle runs inefficiently. Depending on the goals of the sterilization validation, either a full-cycle approach or a reduced level approach of treatment known as a partial cycle approach will be performed. An example of a partial cycle approach is a half cycle approach. Overkill sterilization validations are governed by ISO 17655-1.
Environmental monitoring involves sampling the air, water, and manufacturing surfaces for microbes and keeping surfaces, equipment, products, and raw materials free from microbial contamination. Sterilization validations are used to ensure that the sterilization process can appropriately kill any viable microorganisms in a sample, a product, a material, etc. Thus, sterilization validations support the environmental monitoring process by ensuring that manufacturing equipment, transfer lines, raw materials, and products have live microbes removed or killed before use in manufacturing or by the end-user. Multiple USP guidance documents (USP 1211, USP 1115, USP 1116, etc.) govern environmental monitoring.
Why are environmental monitoring and sterility testing important?
Sterilization validations are a critical quality control step that verifies that sterilization methods effectively kill the live bioburden in a product, piece of manufacturing equipment, material, etc. As microorganisms exist on every surface (including our body), microbes can be accidentally introduced during the manufacturing or packaging process in many ways. Some of the most common examples are contamination through the raw materials used, technicians, tubing/piping used to transfer product between development stages in a process, or the manufacturing environment itself. With such abundant sources of contamination, regular testing of the manufacturing environment and manufacturing processes supports the long-term control of bioburden levels in manufactured products. To this end, environmental monitoring is an important quality control metric. It is particularly critical for verifying your medical device or product is devoid of microbes during various phases of manufacturing, packaging, transportation, and storage, especially for products manufactured under aseptic conditions.
Summary
Overall, both environmental monitoring and sterilization validations are imperative for regulatory approval of medical devices or products. These tests ensure that medical devices, products, manufacturing environments, and packaging are free from viable microbial contaminants and maintain sterility. Maintenance of sterility ensures that patients will not be at risk of infection following device exposure or product implantation. Ensure you choose a contract manufacturing organization that can support you with appropriate environmental monitoring and sterilization validations for your unique medical device or product needs.
Ethide Labs is a contract testing organization that specializes in Sterilization Validations and Environmental Monitoring. Ethide Labs provides in-vitro cytotoxicity tests in-house and outsources in-vivo cytotoxicity work for toxicity testing of medical devices, products, and drugs. Ethide Labs also offers Bioburden Testing, Microbiology Testing, Bacterial Endotoxin Testing, EO Residual Testing, Package Integrity Testing & Cytotoxicity Testing services for medical device companies and allied industries. Ethide is an ISO 13485 certified facility.
References
International Organization for Standardization. Sterilization of health care products- Moist heat- Part 1: Requirements for the development, validation, and routine control of a sterilization process for medical devices. Geneva (Switzerland): ISO; 2006. (ISO 17665-1:2006/(R)2016).
United States Pharmacopeial Convention. <1115> Bioburden Control of Non-Sterile Drug Substances and Products. Rockville, MD, USA. 2021. (USPC <1115>).
United States Pharmacopeial Convention. <1116> Microbiological Control & Monitoring of Aseptic Processing Environments. Rockville, MD, USA. 2021. (USPC <1116>).
United States Pharmacopeial Convention. <1211> Sterility Assurance. Rockville, MD, USA. 2021. (USPC <1211>).
