Particle Counters: The Evolution of Real-Time Viable Monitoring
Particle Counters: The Evolution of Real-Time Viable Monitoring
To talk to Toni about the potential these new technologies can offer, and what is available right now, call 0161 529 2816 or email sales@isocleanroom.co.uk to find out more.
In the contamination control industry, particle counters have long been the primary tool for supporting cleanroom standards across all ISO classifications. By determining contaminant levels at every stage of the production process, these devices ensure product safety and regulatory compliance.
However, a relatively recent innovation, relevant to Life Sciences, is the development of viable particle counters. Unlike traditional units that measure all particles, inert and live dust and debris, these advanced systems detect "live" particles capable of forming colonies and separate this reading from the inert “dead” particles.
At the recent Making Pharmaceuticals show in Coventry, GMP Microbiologist John Cobb (PMT GB) showcased the progress of this technology. His work addresses the most significant flaw in classical microbiology: the five-day wait time for results.
Why Modern Particle Counters are Shifting to RMM
The latest GMP Annex 1 (sections 9.28 and 9.29) now actively encourages the use of Rapid Microbiological Methods (RMM). Traditional particle counters provide immediate data on all particles, but biological monitoring has historically been slow using settle plates and active air samplers.
By integrating RMM, modern viable particle counters provide:
- Immediate Responses: React to bioburden excursions as they happen.
- Trend Analysis: Identify contamination patterns continuously rather than waiting for a lab report.
- Risk Mitigation: Ensure you are in control of your environment at all times.
Technical Innovation: The BAMS Bio-Aerosol Monitoring System
Original RMM developments were often bulky and expensive. However, the BAMS (Bio-Aerosol Monitoring System), developed with technology provider TSI, offers a smaller, lighter, and more economical solution for air sampling.
The BAMS is a Bio-Fluorescent Particle Counter (BFPC). It uses a 405nm laser to determine particle count, size, and biological status simultaneously:
- Inert Particles: Measured and sized based on scattered light.
- Biological Particles: Emit fluorescence when excited by the laser.
While some non-biological materials can fluoresce, the BAMS uses a sophisticated algorithm to filter out these false positives, ensuring high data integrity.
From CFUs to AFUs: Microsecond Results
Traditional air samplers and settle platrs for viable matter relied on growth-based analysis (CFUs), which might only capture 1% of total contaminants. By contrast, the BAMS measures Auto Fluorescent Units (AFUs). This counts the absolute number of cells, including those that are viable but non-culturable, stressed, or dead.
What used to take five days in a laboratory now takes microseconds on the cleanroom floor.
Applications of Autonomous Particle Counters
The benefits of autonomous environmental monitoring were highlighted through several key case studies:
- Facility Recovery: A Pfizer hurricane recovery plan utilised BAMS to quickly identify HEPA filters likely to fail, enabling proactive remediation after an unexpected shutdown.
- HVAC Validation: In a Grade C cleanroom, particle counters determined that the room recovered to zero counts within 20 minutes of an HVAC shutdown, saving hours of unnecessary cleaning time.
- Isolator Monitoring: Continuous monitoring of isolators reduces the need for human intervention, which is the primary source of contamination.
The Future: Robotics and AI in Particle Counting
The industry is moving toward Autonomous Environmental Monitoring. By using robots to move particle counters around the cleanroom, facilities can:
- Eliminate Human Variability: Consistent, automated sampling improves reproducibility.
- Reduce Labour Costs: Minimise the personnel required for manual sampling.
- Enhance Data Integrity: Digital reporting ensures total compliance with modern regulations.
As automation becomes the standard, future particle counters will likely incorporate AI for predictive contamination control, identifying potential issues before they cause a batch failure.
Comparison: Traditional vs. Viable Particle Counters
| Feature | Standard Particle Counters | Viable Particle Counters (BAMS) |
| Detection Type | All particles no breakdown | Inert AND Biological (bacteria, fungi) |
| Result Speed | Real-time | Real-time (eliminates 5-day incubation) |
| Feature | Standard Paticle Counters | Viable Particle Counters (BAMS) |
| Measurement | Particle size/count | AFUs (Auto Fluorescent Units) and particle size/count |
| Annex 1 Status | Required | Encouraged as a "Rapid Method" |
Particle Counters Frequently Asked Questions (FAQs)
Standard particle counters measure the concentration and size of airborne particles, typically ranging from 0.5µm to 5.0µm (and up to 10µm). While traditional units detect inert and viable and make no distinction between the two. Viable particle counters use laser-induced fluorescence to identify biological particles, such as bacterial and fungal spores, in real-time.
The latest Annex 1 revisions encourage Rapid Microbiological Methods (RMM) because they provide immediate data. Unlike traditional settle plates or active air samplers that require 5–7 days of incubation, real-time particle counters allow for immediate intervention if a contamination event occurs, preventing the loss of entire batches.
A BFPC is an advanced type of particle counter that uses an ultraviolet or violet laser (often 405nm) to induce fluorescence in biological molecules like NADH or riboflavin. This allows the device to distinguish between a piece of inert dust and a living microbe, providing an absolute count in Auto Fluorescent Units (AFUs).
Yes. Modern monitoring systems like the BAMS (Bio-Aerosol Monitoring System) can be integrated with robotic platforms to navigate Grades A through D. This reduces human presence, the leading cause of contamination, and ensures consistent, reproducible environmental monitoring without the risk of human error.
Expert Guidance on Particle Counters
These developments are very exciting. It just shows how rapidly our industry is moving – and we work hard to ensure we can take advantage of innovations where they can be of benefit to our clients.
— Toni HorsfieldTo talk to Toni at Isoclean about the potential these new technologies can offer, and what is available right now, call 0161 529 2816 or email sales@isocleanroom.co.uk to find out more. Contact Toni Horsfield at ISO Cleanroom:
📞 0161 529 2816
📧 sales@isocleanroom.co.uk
