Feature image: E. coli Bacteria (CC BY 2.0) by NIAID
Preventing, detecting, and eliminating cleanroom contamination from bacteria, viruses, and spores is an ongoing battle. But a battle that must be fought consistently and methodically in controlled environments for pharmacies, hospital labs, biomedical manufacturing, and other health-related controlled environments. People’s health, and perhaps lives, are at stake. Proper, consistent microbial contamination control not only protects people but also lessens chances of product recalls that affect your organization’s reputation as a safe health-related provider. It also reduces risks of severe fines. Bottom line: cleanroom contamination results in product contamination.
This information is only for education and general guidance. It is vital all cleanroom staff follow the specific standard operating procedure (SOP) of the facility to ensure specific procedures are relevant to a cleanroom’s applications.
What is Your Cleanroom’s Level of Clean?
Depending on what products are created and what tasks are being performed in a cleanroom, there are different classifications or requirements. Each classification has a different cleanliness level regarding particles including microbes.
Class 100 (ISO 5) — strictest or “cleanest” critical environment. This class number refers to how many particles larger than 0.5 microns per cubic foot of air that are permitted. Key points:
All incoming air must go through High Efficient Particle Air (HEPA) filtration. This scrubs air removing most particles from circulating into controlled areas.
Most critical environments use positive pressure inside to prevent unfiltered air from entering when a door is opened. High pressure inside the structure ensures air flows out.
People, equipment, furniture, and supplies are the greatest source of microbial and other types of environmental infiltration. Proper gowning and cleaning introduced objects before entering a Class 100 environment are vital.
Class 10000 and Class 100000 cleanrooms are less strict, allowing more particles per cubic foot of air, but are still vigilant about microbial contamination in healthcare-related facilities.
Cleanroom Contamination Control
Eradicating microbes requires diligence across the life cycle of cleanroom processes. From cleanroom design to standard operating procedures to cleanroom cleaning protocols, thousands of decisions must be made and cleanroom staff must be trained and compliance monitored.
Removing or killing microbes from a cleanroom is complex because microorganisms themselves are complex. What eradicates one type of microbe may be less effective on other organisms especially spores. Spores are not living organisms, but after even years of dormancy are capable of becoming activated under the right conditions. Spores can continue to exist in the harshest environments against the toughest of disinfectants and detergents.
The diversity of organisms is why our pharmacy cleanroom cleaning procedure checklist includes recommendations for using multiple types of cleanroom chemicals and rotation of chemicals for periodic cleaning cycles.
Sources of Cleanroom Contamination
Understanding where contamination can creep in is the first line of defense so that you not only can minimize microbial contamination from being introduced, but also tells you where to monitor for best detection. See our cleanroom cleaning procedures guide for information on identifying sources of cleanroom contamination.
Controlling Microbial Contamination
Following aseptic techniques is the primary way to prevent introduction or cross-contamination of organisms, dirt, lint, and other contaminants that jeopardize the safety of your cleanroom products. The basic concept of this protocol is to minimize or eliminate exchange of contact between sterile and non-sterile elements. This includes the air. Unidirectional air flow referred to as laminar flow is used to ensure that air is not disrupted from its filtration sources to the materials, equipment, or products. This ensures that only non-contaminated air comes into contact with anything related to producing the final product.
Maintaining a cleanroom’s air quality and other pathways of contamination such as non-sterile materials, equipment, or apparel touch sterile elements is paramount. This requires proper standard operating procedures as well as the training off staff to follow them. The second line of defense is monitoring how well the protocols are followed.
Each cleanroom has its own procedures that suit its application, but typically these steps are required:
Minimizing Contamination
- Consistently test raw materials for quality and sterility.
- Properly construct and maintain positive pressure and filtration systems.
- Permit only trained staff and limit the number in the environment as even trained personnel are the biggest cleanroom contamination risk.
- Strictly adhere to rules that prevent exposing sterile items to non-sterile items including using all appropriate sterile instruments and apparel. General guidelines for sterile cleanroom apparel (order of donning is determined by cleanroom SOP) are below and in our discussion about what to wear in your cleanroom based on cleanroom class:
- Sterile gloves. After thorough hand and arm washing as well as fingernail cleaning with antibacterial soap, dry with sterile wipe. Don sterile gloves carefully following manufacturer procedures for maintaining sterility.
- Face mask. Cover fully the nose and mouth and adjust the mask to a fit snugly. Wear a beard cover if needed.
- Hood. Secure elastic closure to fit snugly at the face.
- Coverall. Carefully remove the coverall from its protective packaging ensuring it does make contact with other objects including the floor. Step into the coverall and then insert arms.
- Disposable shoe covers. Cover shoes with covers pulling them up over the coveralls.
- Goggles. Use disposable one-time use or properly autoclaved goggles ensuring a tight fit to the face.
- Second set of sterile gloves. Carefully don a second set of sterile gloves ensuring they fit over the sleeves of the coverall.
- Minimize the potential for contamination that escapes from your manufacturing operations.
- Regularly test and maintain the environment’s structure, equipment, and fixtures.
Monitoring contamination
- Monitor strategic areas to detect missed cleaning procedures and improper apparel and other human-introduced contamination. See our tips on monitoring for cleanroom contamination.
- Monitor continuously all air filters, filter equipment, and the air flows.
- Re-certify the cleanroom periodically.
Removing contamination
- Regularly clean the facility utilizing the correct cleanroom cleaning solutions and critical environment cleaning procedures that are precisely followed and carefully monitored.
- Cleaning per your standard operating procedures (SOP) with appropriate cleanroom wipes, lint-free mops, and specialized tools such as isolator cleaning tools. Learn more about the benefits of presaturated cleanroom wipes.
- Compare cleanroom wipe materials for effectiveness for each application in your facility.
- Carefully adhere to spill containment and clean-up procedures.
Enforcing Proper Cleanroom Procedures
The key is training staff to thoroughly understand the processes and protocols that keep a cleanroom environment sterile and clean. Repetitive communication and easy access to documented procedures (SOP) as well as monitoring with remediation for any compliance issues. Much of the challenge is in developing consistent behavior and habits among all cleanroom personnel which requires diligence.