In industries such as life sciences, healthcare, and manufacturing, cleanrooms play a vital role in maintaining strict microbial contamination control. These controlled environments rely on comprehensive decontamination programmes, often incorporating the rotation of disinfectants combined with sporicidal agents. While these practices are essential for preventing the spread of contaminants, they may inadvertently introduce new sources of contamination into the cleanroom environment.

What if the very solutions intended to combat contamination pose a potential threat themselves? The need for simple yet effective protocols for residue management becomes evident, as they are an indispensable part of an overall contamination control strategy.

Residue management refers to the systematic approach of identifying, assessing, and managing the residues left behind by disinfectants, cleaning agents, and other processes within a cleanroom. By recognising the impact of residue accumulation and implementing proper management techniques, cleanroom operators can mitigate the risk of contamination, safeguard product integrity, and maintain a consistently sterile environment.


What is residue, and why is it important to manage residue in cleanrooms?

Before delving into the significance of residue management in cleanrooms, let’s set the scene by understanding what residue actually refers to in this context. Residue in cleanrooms pertains to the remnants or traces left behind by sporicidal agents and disinfectants after the cleaning and decontamination process. Despite thorough cleaning efforts, these residues can persist on surfaces, equipment, and even in the air.

The importance of removing sporicidal and disinfectant residue cannot be overstated. Firstly, these residues can serve as potential sources of future contamination. Over time, they can accumulate, providing a breeding ground for microorganisms to thrive. This compromises the overall cleanliness and sterility of the cleanroom environment, undermining the efforts put into decontamination programs.


What do industry regulations say?

Industry regulations, such as ISO standards, Annex 1 of the EU GMP, and Good Manufacturing Practices (GMP) emphasise the importance of maintaining a consistently sterile environment. This does not necessarily specify but would suggest minimising the presence of residues as part of an overall contamination control strategy.

ISO 14698 provides guidelines for biocontamination control in cleanrooms, including the monitoring and control of airborne and surface microbial contamination. While it does not specifically address residue management, the general principles of maintaining cleanliness and minimising sources of contamination apply to residue removal as well.

Annex 1 of the EU GMP, which pertains to the manufacture of sterile medicinal products, emphasises the need for cleanrooms, proper cleaning and disinfection procedures, and environmental monitoring to ensure the sterility and quality of pharmaceutical products. While it does not have explicit guidance on residue management, residue removal is an inherent part of the cleaning and disinfection processes required by the Annex.

Even where there isn’t specific guidance about residue management protocols, cleanroom operators should consider implementing residue management practices to maintain a clean and sterile environment, in line with the broader principles outlined in ISO 14698,  Annex 1 of EU GMP, or in the US, the GMP.


What are the risks of neglecting residue management?

Neglecting residue management can lead to several risks and consequences within the cleanroom environment. Firstly, the accumulation of residues can compromise the effectiveness of disinfection processes. Residues left on surfaces may act as physical barriers, preventing disinfectants from properly contacting and eliminating microorganisms.

Furthermore, residues can interfere with the performance of critical equipment and sensitive instruments used in cleanroom operations. They can impair the functionality of machinery, affect product quality, and even lead to costly equipment breakdowns or failures.

The presence of residues also increases the potential for cross-contamination. Microorganisms may attach themselves to these residues and spread throughout the cleanroom, contaminating other surfaces, products, or personnel. This can have detrimental effects on the integrity of products, jeopardise patient safety, and hinder research or manufacturing processes.


How can you mitigate residue buildup?

To mitigate the buildup of residue in cleanrooms, it is crucial to implement simple yet effective protocols for residue management. These protocols aim to identify, assess, and remove residues regularly, ensuring a clean and sterile environment. Here are some key steps and considerations for effective residue management:


  1. Measure and monitor residue

Implement “Residue on Evaporation” (RoE) measurements. RoE is a widely recognised method for measuring the potential for residue. By conducting regular RoE tests, cleanroom operators can monitor the amount of residue left behind by disinfectants and adjust cleaning protocols accordingly.

  1. Use low-residue cleaning and disinfectant products

Using low-residue cleaning and disinfectant products will help limit residue. At AGMA, our chemists in our labs in Haltwhistle develop our cleaning and disinfectant products, carefully to minimise residue and build-up. 

  1. Utilise residue removal options

There are several options for removing residue. These include rinsing, wiping, or using specific cleaning agents designed for residue removal. It is very important that these methods are employed after your disinfectant has been applied for the required wet contact time and allowed to dry.

At AGMA we recommend WFI Quality Water for rinsing away residue. While some cleanroom operators use additional solutions for residue removal, particularly if their products are prone to build-up, we recommend this approach because it removes the need for unnecessary chemicals and complex procedures. Our products are designed to meet cleaning and disinfection needs with just four different product types: neutral detergent to clean, disinfectant alcohol to disinfect, Zyceine to rotate in a sporicide, and sterile high purity water to rinse any residue. This can help cleanroom operators save on costs and optimise efficiency, while ensuring compliance. 

  1. Incorporate residue removal into cleaning PM

To ensure the consistent removal of disinfectant residue, it is essential to introduce a specific step dedicated to residue removal into the cleaning Preventive Maintenance (PM) schedule. This step should be performed regularly, with the frequency determined based on the results of RoE measurements and industry guidelines. 

Important safety notes for residue removal:

During the residue removal process, it is crucial to prioritise safety and adhere to best practices. Consider the following important safety notes:

  • Timing of rinsing applications: 

When incorporating rinsing as a residue removal method, it is vital to ensure that it is done only after the sporicide or disinfectant has been applied for the desired wet contact time and allowed to dry. Rinsing surfaces too soon can dilute the disinfectant, potentially reducing its effectiveness in controlling microbial growth. By following the recommended contact time and allowing sufficient drying time, you can maximise the efficacy of the microbial control program.

  • Use of sterile and micron filtered products cleaning agents and equipment:

Using non-sterile agents or contaminated equipment can introduce additional sources of contamination, defeating the purpose of residue removal efforts. 

At AGMA, We provide a choice of both sterile and 0.2 micron filtered products developed for use in areas ranging from Grade A (ISO Class 4) cleanrooms to unclassified areas where 0.2 micron filtered disinfectants and detergents are required for a good standard of cleanliness and hygiene.

By understanding and implementing these protocols, you can fortify your contamination control practices, optimise operational efficiency, and achieve the highest levels of cleanliness in your cleanroom environment.

Recommended Products

AGMA sterile high purity water

Our Sterile High Purity Water is one of the simplest cleanroom solvents for surface cleaning, ensuring no disinfectant residue is left behind in your cleanroom environment. This product comes as a fluid, which is perfect for mopping and dosing wipes, and is also available in a trigger spray bottle.

At AGMA, we have been formulating chemical solutions for over 50 years, and have an expert team that can help you find the perfect product. Discover the healthcare products we offer or get in touch today.