I have been tasked with establishing and implementing a microbial monitoring program for our new non-sterile ISO Class 6 cleanroom that packages medical devices for terminal sterilization by gamma radiation. What resources are available to assist me?
Microorganisms (bacteria, molds, and yeasts) found in cleanrooms in the air and on surfaces are viable particles that can contaminate and/or damage products, equipment, and even the cleanroom itself. As microorganisms replicate, they produce byproducts that cause additional damage to the surfaces to which they are attached. Microorganisms found in cleanrooms are capable of growing and reproducing in a wide variety of environments. Therefore, a microbial monitoring program is important to determine the total number of particles, both viable and non-viable, in the cleanroom.
Why establish a program?
There are several positive advantages of establishing and implementing a microbial monitoring program. A microbial monitoring program can:
• Monitor cleanroom production and laboratory environments
• Evaluate sanitization and disinfection efficacy
• Monitor and qualify cleanroom personnel
• Validate cleaning processes of and in the cleanroom
However, the microbial monitoring program is only capable of what is proven to work, documented, implemented, and maintained.
There are several industry and international references that can guide you through this process. I use:
• IEST-RP-CC023.3, Microorganisms in Cleanrooms (IEST will publish in 2014)
• ISO 14698 – 1 & 2, Biocontamination Control in Cleanrooms and Associated Controlled Environments
• USP <1115> Bioburden Control of Non-sterile Drug Substances and Products
A microbial monitoring program should be able to enumerate and identify the recovered microorganisms. Microorganisms enter the cleanroom via the environment surrounding the cleanroom, on personnel entering the cleanroom, and tools, product, and process equipment. Therefore, when creating a microbial monitoring program for the cleanroom, it is important to assess the cleaning of the areas surrounding the cleanroom, the gowning and work practices of the personnel entering the cleanroom, and the cleaning of the tools, product, and process equipment entering the cleanroom.
Risk analysis
One first should perform a risk analysis to the product and the process for potential contamination. This should include:
• Is the product and/or process sensitive to changes or extremes in temperature and/or relative humidity?
• What is the risk of microbial contamination to the product and/or process?
• What are the customer’s specifications?
• Are there any safety concerns?
• Have there been any changes in the existing cleanroom facility?
• What are the regulatory requirements?
The cleanroom HVAC system contributes to the control of microorganisms by removing microorganisms and recirculating the air at prescribed temperatures and relative humidity levels. The positive pressure of the cleanroom to the environment surrounding the cleanroom additionally prevents migration of the microorganisms into the cleanroom. Therefore, the HVAC system must be routinely checked for compliance to ISO 14644-1 & 2, Cleanrooms and associated controlled environments – Part 2: Specifications for testing and monitoring to prove compliance with ISO 14644-1.
The personnel entering and working in the cleanroom contribute the most significant amount of microbial contamination to the cleanroom. Therefore, proper gowning and adherence to recommended cleanroom personnel practices is critical to the control of the microbial contamination in the cleanroom. IEST-RP-CC003.4, Garment Considerations for Cleanrooms and Other Controlled Environments provides guidelines for gowning at each classified cleanroom level. IEST-RP-CC027.2, Personnel Practices and Procedures in Cleanrooms and Controlled Environments provides guidelines for the behavior of the people working in the cleanroom and cleaning of the tools and process equipment prior to entering the cleanroom.
Before implementation of a microbial monitoring program, an effective cleaning program is developed. IEST-RP-CC018.4, Cleanroom Housekeeping: Operating and Monitoring Procedures provides guidelines to establish and validate an effective cleaning program. Sanitizing and disinfecting agents are determined, validated, and implemented into the cleaning, sanitizing, and disinfecting program for the cleanroom. There are many types of sanitizers and disinfectants available so the selection of a specific agent should be based on its intended use, surfaces or air with which it is used, safety of use, and the microorganisms in the cleanroom to be controlled. The microbial monitoring program will evaluate the efficacy of the cleaning validation program initially and on-going.
Sampling
Once the risk analysis is completed, the number and location of sampling sites and frequency of sampling is determined. Examples of typical sampling sites are:
• Near open and/or filled containers or filling line
• Room air near work areas
• Water at point of use
• Floors, walls, door handles, curtains
• Personnel
Additionally, the method of air and surfaces microbial sampling is determined and proceduralized. All procedures should include:
• Purpose
• Scope
• References
• Specifications—including establishment of alert/action levels
• Methods
• Map of sampling locations
• Corrective action—resolution of out-of-specification results
There are several different methods of air sampling for microorganisms. Selection of the collecting apparatus is very important. There are four typical methods of air sampling for microorganisms:
• Impactors
– Slit
– Sieve
– Centrifugal
– Cyclone
• Liquid impingers
• Filter collection
• Sedimentation
Sampling surfaces for microorganisms is typically performed using a contact plate for flat surfaces or swab sampling of irregular surfaces.
Ongoing monitoring
Thorough training and documentation of the training of all employees working in and out of the cleanroom in all procedures is performed initially and at regularly scheduled intervals.
Once the microbial monitoring program is established and implemented, there must be continuous monitoring and analysis of the data, including evaluation of trends. The criticality of the cleanliness of the cleanroom to the positive outcome of the process and product is dependant on the constant, consistent evaluation of the data. Corrective action taken to resolve out-of-specification results should first “do no harm.” A typical failure analysis should include:
• A description of the non-conformance
• Possible cause(s) of the problem—ask “why” five times
• Identification of the person(s) responsible for creating and implementing corrective action
• A description of the corrective action and a schedule for implementation
• Evaluation of effectiveness of corrective action
It’s worth the effort to define the microbial monitoring program properly. However, the establishment of the program is only part of the process. A working program also provides for ongoing evaluation and formalizes measures to take when criteria are not met.
Once implemented, a microbial monitoring program gives the cleanroom managers a useful tool to survey the current and past status of the cleanroom.
Jan Eudy is a Cleanroom/Contamination Control Consultant as well as a Fellow and Past President, Institute of Environmental Sciences and Technology. She is located in Carolina Beach, N.C. and can be reached at [email protected].
This article appeared in the June 2014 issue of Controlled Environments.
