What is meant by a Contamination Control Strategy (CCS) as defined in Annex 1 of the EU GMP Guidelines?

For manufacturers of pharmaceutical products such as medicinal products, vaccines, etc., and their suppliers, any type of contamination leading to product or production losses poses a significant risk. Contamination with foreign particles, such as a case involving metal particles, harmful chemicals such as ethylene glycol or diethylene glycol, or microorganisms, e.g. Burkholderia cepacia complex (BCC), can have far-reaching consequences in addition to the direct costs of discarded products and lost production time. Patients suffering harm with claims for compensation, product recalls, and even supply shortages of individual medicinal products or groups of medicines are further possible consequences.

1. Requirements

In accordance with applicable guidelines, manufacturers should design their production facilities, equipment and processes and implement a Quality Risk Management (QRM) system in such a way as to ensure adequate contamination control, with the aim of minimising or detecting contamination. As the measures concern various phases of a manufacturing process and often fall within the remit of different departments (e.g. Quality Control, Quality Assurance, Manufacturing or even Engineering), it was not always ensured in the past that the data obtained during the process - e.g. from the initial qualification of equipment and validation of processes, from process controls and from ongoing environmental monitoring - was linked together. This was particularly the case when responsibility was embedded across departments. This also applies to corrective and preventive actions (CAPA) taken on the basis of deviations and trend analyses, which were implemented only on a department-specific basis but were neither integrated into a strategy for a holistic approach nor did information flow to neighbouring areas of responsibility. There was often a lack of linkage between all critical control points across the various areas of responsibility, and the effectiveness of all controls (design, procedures, technology and organisation) was not assessed.

However, such a holistic approach is proposed in Annex 1 (2022) of the EU GMP Guidance on Particulate, Microbiological and Pyrogenic Contamination.

2. Scope of Annex 1

Annex 1 (2022) 'Manufacture of Sterile Medicinal Products' addresses the demanding challenge of contamination control across a wide range of sterile product types:

• Finished dosage forms, finished products or medicinal products
• Active substances, active ingredients or pharmaceutical active ingredients
• Excipients
• primary packaging materials

Contrary to what the title suggests, Annex 1 does not deal solely with the status of "sterile" products. It also contains guidelines and recommendations for products that are not intended to be sterile:

"The intent of the Annex is to provide guidance for the manufacture of sterile products. However, some of the principles and guidance, such as contamination control strategy, design of premises, cleanroom classification, qualification, validation, monitoring and personnel gowning, may be used to support the manufacture of other products that are not intended to be sterile such as certain liquids, creams, ointments and low bioburden biological intermediates, but where the control and reduction of microbial, particulate and endotoxin/pyrogen contamination is considered important."

In general, Annex 1 draws heavily on the principles of quality risk management, but also contains specific and explicit requirements, e.g. to develop a CCS.

The intention of Annex 1 can be understood as ensuring comprehensive contamination control, whereby the approach and level of detail should be appropriate to the nature of the process and the product. Depending on the process and product type, the intent of Annex 1 can be understood as an appropriate approach to ensuring the following points:

• Sterility assurance
• Control of biological load / low biological load (bioburden)
• Control of pyrogens / endotoxins
• Control of foreign particles

The control of chemical composition or the detection of chemical impurities is often handled separately from traditional contamination control, falling within the scope of analytical quality control, which verifies the specifications of raw materials, active ingredients and the final product.

3. The ECA Guide 'How to Develop and Document a Contamination Control Strategy'

An ECA CCS Task Force, comprising experts from industry, laboratories and the regulatory sector, has examined what a CCS might look like and what content it could include, and has drawn on these findings to produce a practical guide. The ECA CCS Task Force document summarises this as follows:

"Contamination Control Strategy (CCS) – A planned set of controls for microorganisms, endotoxin/pyrogen and particles, derived from current product and process understanding that assures process performance and product quality. The controls can include parameters and attributes related to active substance, excipient and drug product materials and components, facility and equipment operating conditions, inprocess controls, finished product specifications, and the associated methods and frequency of monitoring and control. Additional elements of potential contamination source (e.g., virus, cross-contamination) being identified should be included in the CCS as applicable regarding to one’s company’s conditions and requirements "

Annex 1 specifies that such a contamination control strategy must also be reviewed regularly and updated where necessary. The content is not set out in detail in Annex 1, but it is advisable to use the general structure of Annex 1 as a basis, as this facilitates the preparation of a CCS. The ECA guidance also follows this structure:

"2.5 The development of the CCS requires sound technical and process-related knowledge. Potential sources of contamination include microbial and cellular residues (e.g. pyrogens, endotoxins) as well as particles (e.g. glass and other visible and non-visible particles).
The elements that should be included in a documented CCS include (among others):
I. Design of the facility and processes, including the associated documentation.
II. Premises and equipment.
III. Personnel.
IV. Utility systems.
V. Raw material controls - including in-process controls.
VI. Product containers and closures.
VII. Supplier qualification - e.g. suppliers of critical components, sterilisation of components and single-use systems (SUS), and critical service providers.
VIII. Management of outsourced activities and the availability/transfer of critical information between parties, e.g. in the case of contract sterilisation services.
IX. Process risk assessment.
X. Process validation.
XI. Validation of sterilisation processes.
XII. Preventive maintenance - maintenance of equipment, utility systems and premises (scheduled and unscheduled maintenance) to a standard that ensures there is no additional risk of contamination.
XIII. Cleaning and disinfection.
XIV. Monitoring systems - including an assessment of the feasibility of introducing scientifically sound, alternative methods that optimise the detection of environmental contamination.
XV. Prevention mechanisms - trend analysis, detailed investigation, root cause analysis, corrective and preventive actions (CAPA) and the need for comprehensive investigative tools.
XVI. Continuous improvement based on the information obtained from the above points."

It should be noted that this list contains only headings and keywords and does not claim to be exhaustive. Individual points may not be relevant for certain companies, but other aspects may be of significance, such as

• Pest control
• Virus security (e.g. accidental pathogens)

It should be noted that a CCS must always be drawn up individually for each company.

The ECA CCS Guide provides assistance with this; it also offers a template that can be used to create a CCS and allows for customisation. It can be downloaded free of charge from the ECA Foundation website after registration.

4. Literature and sources

• 1. World Health Organisation, Full List of WHO Medical Product Alerts
• 2. U.S. Food & Drug Administration, Recalls, Market Withdrawals & Safety Alerts, Recall of Diocto Liquid and Diocto Syrup Manufactured By PharmaTech, LLC Due to Possible Product Contamination
• 3. European Commission, Eudralex Volume 4 - Good Manufacturing Practice (GMP) guidelines
• 4. EudraLex - Volume 4 - Good Manufacturing Practice (GMP) guidelines, Annex 1, Manufacture on Sterile Medicinal Products (fully applicable 25.08.2025),
• 5. GMP News "ECA publishes Contamination Control Strategy Guide" from 8 February 2022
• 6. ECA Contamination Control Task Force Update from 15 July 2022,
• 7. ECA - Contamination Control Strategy Guide - Online Training Recording
• 8. Pharma Technologie Journal, Gute Hygiene Praxis, 3. Revised and expanded edition, Editio Cantor Verlag
• 9. Hygiene in der Arzneimittelproduktion, Michael Rieth und Norbert Krämer, Wiley-VCH

Please also see a selection of training courses on the topic contamination control on the ECA GMP Compliance website.