maintaining environmental monitoring and process validation takes a holistic approach with bespoke elements

Settle plate stands, microbial air sampler spare heads, tripods, bespoke media and instrument calibration services are the details that can make the difference

The best environmental monitoring and validation processes are designed with the desired end result in mind from the outset.

At Cherwell Laboratories we have designed and produced media formulations, settle plate stands, contact plate carriers and air sampler tripods to ensure you get the precise results from your EM program that you need.

We have also created bespoke packaging solutions, such as the one we developed for Great Ormond Street Hospital, and our special barrier packs for gamma-irradiated media.

Additionally, we offer a tailored calibration service for your SAS air samplers, including an onsite option, to ensure your instruments are also in top condition.


let's discuss your requirements

fine-tuning em: prepared media accessories and calibration services

How to get reliable environmental monitoring data every time

Use the right media and position it precisely

Electro-polished stainless steel

You might need bespoke media set a specific distance above the surface. Use plate carriers to ensure your plates are transported safely, and settle plate stands to support your media for repeatable results.


Keep your instruments in optimum order

Top performance levels maintained

Make sure your SAS and ImpactAir microbial samplers are perfectly calibrated to ensure optimum performance and reliability for repeatable results you can trust.

Position your samplers perfectly

Use accessories for precision placement

Position your SAS microbial air samplers precisely using floor standing tripods and table top stands for reliable results you can trust. Keep a supply of spare sampler heads as well.


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Frequently asked questions

About Our Accessories and Calibration Services

What is the maximum exposure time for settle plates?

Settle plates are used to monitor the level of viable particles in the environment through a process of passive air sampling. A viable particle settles on agar plates at a rate dependent on its characteristics and the airflow in the environment.

EU GMP Guide Annex 1 has recommended that 90mm settle plates can be exposed in cleanroom environments for up to 4 hours. However, agar plates may dry out during long exposures where the rate of air exchange is high. So, it might be necessary to use deep filled settle plates, or replace the settle plate after a shorter time to ensure satisfactory growth promotion after exposure.

How much air should we sample?

Typical requirements suggest 1,000 litres per air sample in high risk areas, such as: grade A filling lines, grade B clean rooms, operating theatres etc. As the criticality of the area reduces, the sample size can be reduced. The aim is to achieve a representative sample; so where higher counts would be expected, a smaller sample produces a more realistic number of cfu to count.

Do I need to store my prepared media in the fridge?

The majority of our prepared media can be stored in ambient conditions, not exceeding 25ºC. There are only a small number of very specialist products that require different storage conditions.

We have never specified refrigeration as a storage condition for our general media as this causes excess condensation and can result in very wet agar, rendering it impossible to use.

Our environmental monitoring requirements have changed. Can you help us create new processes?

Yes. We have almost thirty years' experience with helping pharmaceutical and associated industries deliver environmental monitoring processes critical to the manufacture of heavily regulated products.

We supply every component you need to create environmental monitoring processes. We also offer bespoke formulations, accessories and even packaging solutions for organisations with very particular needs.

Get in touch today. Let's discuss your requirements.

What is the difference between general purpose and selective growth media?

Selective growth media contain components that will inhibit the growth of some types of microorganisms, while supporting the growth of others.

General purpose media, such as Tryptone Soya Agar, are used to produce total counts. While selective media, such as XLD for Salmonella species, are used to test presence/absence of specific types of microorganism.

cherwell is different

Supplying products is only the start


The best products prepared for you

Our Redipor® media products are batch tested, QC certified and delivered when you need them


Bespoke accessories and services

We provide additional equipment or services to make your environmental monitoring more effective


Best customer service

We build long-standing client relationships on understanding, commitment and trust


get our latest environmental monitoring ebook

The Environmental Monitoring Processes and Validation Guide

We cover the key changes to the revised draft of EU GMP Annex 1 - Manufacture of Sterile Medicinal Products.

What does it mean for your environmental processes?

Download Guide

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