Written by: Domhnall Mc Gowan M.Sc.
Depending on your global location, the product you are manufacturing, or what regulatory body you are working under, your facility may have different requirements for maintaining cleanliness or aseptic conditions. However, one factor is common across all – you must avoid or minimize the introduction of contamination (viable and non-viable particles) into your cleanroom.
Your cleanroom has been designed and built with this function in mind. It has been built with special construction materials which do not produce particles or allow microbial growth, incorporates high efficiency particulate air (HEPA) filters to remove air particulates from incoming air, and has been designed to utilizes positive and negative air pressures which inhibit the movement of particulates into certain areas, to name just a few special features.
However, once this incredibly designed space moves into operation you must be aware of the external factors that can compromise the integrity of your facility.
Personnel and Materials
Humans are one of the biggest sources of contamination to a clean facility. We are walking ecosystems and can shed hundreds of thousands of particles as we move. One of the most commonly found microorganisms during environmental monitoring in cleanrooms is Micrococcus, a family of bacteria found on human skin and upper respiratory passages. Alongside personnel, movement of equipment and materials into your cleanroom can also pose a danger to its cleanliness, as the surface of these items can be home to bioburden that has been picked up while being handled outside the cleanroom.
Nevertheless, you cannot eliminate these items from your facility so you must control the risks associated with them through proper procedures. Factors to consider to properly mitigate these risks are:
Gowning:
A Gowning SOP is usually one of the very first SOPs written for any cleanroom facility. The act of removing “street” clothes and donning a sterile or aseptic gown, greatly reduces the risk of personnel carrying in contamination. However, a gowning procedure has many components which can impact its effectiveness. Here are some questions to ask:
Are we using the correct gowning materials?
There are many types of gowns and gowning accessories on the market, and they all have distinct applications. Without proper review it can be easy to pick the wrong one for your facility.
Is our procedure complex or straightforward? Is our gown easy to put on or is it quite difficult?
Most gowning procedures make sense on paper but how easy is it to follow in real life? Personnel are humans and thus a gowning procedure is open to human error. If just one person is not following the procedure correctly then your whole facility is at risk
How robust is our training and gowning qualification?
This question is possibly the most important because if you are not adequately training your personnel in the proper gowning practice and then testing them correctly, you are setting yourself up for contamination hits.
Proper Decontamination
This applies to both materials and personnel. For materials this means that you have considered the most appropriate disinfection agent for the material type and stage of transfer, and that you are adhering to proper contact time to ensure that you are adequately removing possible contaminants from the material surface.
For personnel, proper decontamination comes down to glove hygiene. Personnel should be hyper vigilant of what items/surfaces they touch while inside the facility and cleanroom. 70% IPA should be available throughout the facility to allow personnel decontaminate their gloved hands whenever they need to.
Strict movement procedures
The flow of personnel and materials within your facility can also have an impact on contamination sources. Any manufacturing or critical step space should adhere to a unidirectional movement flow to limit the entry points for contamination. Additionally, materials should be restricted in the pathways they can move around the facility. This allows you to have more control over their pathways and introduce select points for decontamination.
Maintenance
Maintenance of your facility is important to maintain the components which keep the facility clean. If you do not have an appropriate maintenance strategy, then your cleanroom and overall facility will be at risk of “breaking down”. For clean room facilities, proactive maintenance strategies are the most commonly employed to avoid unplanned downtime. Planned Preventative Maintenance (PPM) sets out a schedule of maintenance activities where every critical piece of equipment undergoes checks. This strategy also incorporates planned replacements, even if the component appears to be working ok, to further avoid component failures.
In terms of cleanroom cleanliness, at a minimum you should have a maintenance strategy for HEPA filters, Biosafety cabinets or other type of critical production equipment, and air pressures, as these items are the barriers to airborne contamination in your cleanroom and protect your product.
Cleaning program
Similar to your PPM program, cleaning is a key component in the maintenance of your facility. No matter how robust your control procedures are it is likely that some bioburden will always make its way into your cleanroom. When it does it must be removed. Implementing a strong Cleaning and Sanitization procedure will ensure that any present bioburden is removed regularly. Areas which must be considered when developing your cleaning program are:
1. Detergent v Disinfectant v Sporicidal
It is important to include all 3 of these cleaning reagent types in your program, however planning the frequency of use for each must be carefully considered to avoid common mistakes such as:
a. Microbial resistance: Depending on the disinfectant type, without rotation resistance could occur.
b. Build-up of residue: If too much residue builds up it can create a barrier to effective disinfection.
c. Damaging effects to equipment: The overuse of harsh cleaning chemicals can cause corrosive and damaging effects to some equipment components.
2. Cleaning Types and Frequency
It is important to define different levels and frequencies of for cleaning activities. You should disinfect work surfaces everyday with 70% IPA but you don’t need to use a sporicidal every day. Your ceilings don’t need to be cleaned as often as your floors. What cleaning agent do you have in case of an emergency?