In the field of microbiological monitoring, the Slit to Agar method represents a significant innovation. This article explores how this technology works as well as the differences between this method and traditional sampling methods.
What is Slit to Agar technology?
Slit to Agar technology is an advanced variation of traditional microbiological sampling. It works by drawing air through a narrow slit that ensures a controlled, unidirectional airflow. The air is then directed onto a rotating agar plate, which continuously exposes a fresh surface. This process enables efficient particle capture, reducing the risk of microbial overlap and keeping captured microorganisms viable for subsequent analysis.
The narrow slit and unidirectional airflow allow the capture of very small particles. The efficiency of air samplers is based on an index called d50. The lower this value, the more efficient the sampler.
In a microbiological air sampler using an impactor, for example, the D50 index indicates the particle size that is captured with 50% efficiency. If a sampler has a D50 of 2 micrometres (µm), it means the device will collect 2 µm particles with a 50% probability. Particles larger than 2 µm will be collected more efficiently, while smaller particles will be collected less efficiently.
Slit to Agar technology has a D50 of 0.42 and 0.53; other samplers, such as Sieve sampler A and Sieve sampler B, have values of 1.6 and 1.11 respectively.
The rotating agar plate not only captures particles, but also keeps microorganisms alive, promoting their growth into visible colonies that can be analysed and identified at species level.
One of the key features of Slit to Agar technology is the ability to perform continuous sampling for up to 8 hours. This capability is ideal for monitoring entire production processes in critical environments, ensuring constant surveillance without the need to frequently replace agar plates.
After capture, viable particles on the agar plate are incubated to allow microbial colonies to grow. These colonies can then be analysed and identified at species level, providing detailed information on the microbial contamination present in the monitored environment.
Comparison with traditional methods
Traditional microbiological sampling methods, such as sieve impactors or settle plates, operate based on different principles.
Impactors draw air through a series of holes that direct particles onto an agar plate, while settle plates are exposed to the air, allowing particles to fall by gravity.
Sieve impactors have variable efficiency, influenced by air velocity and hole size. Settle plates, on the other hand, have very low efficiency and are not suitable for detecting smaller particles or for accurate monitoring.
Unlike Slit to Agar technology, traditional methods do not allow continuous monitoring. Sampling is usually short and requires downtime between sessions to replace agar plates, making the process less efficient.
After sampling, agar plates are incubated to allow microbial colonies to grow. However, identification may be limited by the device’s ability to keep captured microorganisms viable, affecting the accuracy of the results.
Key differences with traditional methods
Slit to Agar technology offers several advantages over traditional methods.
- Sampling continuity: enables prolonged and continuous sampling, whereas traditional methods are intermittent.
- Collection efficiency: captures smaller particles and keeps microorganisms viable, improving monitoring accuracy.
- Regulatory applications: designed to comply with new regulatory standards such as Annex 1, whereas traditional methods may not fully meet these requirements.
Slit to Agar and regulatory compliance
Slit to Agar technology is perfectly suited to ensure full compliance with regulations, particularly with:
- ISO 14698-1 and ISO 14698-2 These standards are part of the ISO group addressing microbiological contamination in controlled environments, such as cleanrooms and laboratories. ISO 14698-1 covers general requirements for the assessment and control of microbiological contamination in clean environments. It includes guidelines for the use of microbiological samplers. ISO 14698-2 provides specific guidance on microbiological sampling and testing methods, including requirements for the use and maintenance of microbiological air samplers.
- EN 17141:2020 This European standard defines requirements for managing microbiological contamination in controlled environments, particularly in laboratories, cleanrooms and pharmaceutical facilities. It provides guidance for microbiological air monitoring, including specifications for microbiological samplers.
- EU GMP Annex 1 (Good Manufacturing Practice) Annex 1 of the EU Good Manufacturing Practice (GMP) provides detailed guidelines on controlling microbiological contamination in sterile pharmaceutical production environments. It also defines requirements for environmental monitoring, including microbiological samplers.
Applications of Slit to Agar technology
Slit to Agar technology can be applied in different contexts. Let’s explore them.
Use in pharmaceutical laboratories
In pharmaceutical laboratories, Slit to Agar is used to ensure that production processes comply with quality and safety standards by continuously monitoring microbiological contamination.
Applications in hospitals and clinics
In healthcare environments, Slit to Agar technology helps monitor and control microbial contamination, reducing the risk of healthcare-associated infections and improving patient safety.
Compliance with regulatory standards
Slit to Agar complies with several regulatory standards, including those set out in GMP Annex 1, ensuring that microbiological monitoring processes align with industry best practices.
What are the advantages of Slit to Agar technology
Slit to Agar provides greater accuracy in microbiological sampling compared to traditional methods, capturing smaller particles and keeping them viable for more precise analysis.
Furthermore, the controlled airflow and rotating agar plate reduce the risk of microbial overlap, improving the reliability of sampling results.
Slit to Agar technology also ensures superior efficiency in the collection and identification of microorganisms, enabling continuous and accurate monitoring.
Finally, Slit to Agar is designed to integrate with continuous monitoring systems, offering a complete solution for microbiological control in critical environments.
