Prepared Microbiological Media: Pros and cons

By Gill Power

The question of whether to use externally sourced prepared media or whether to produce in-house is one that goes beyond cost and preference. For some manufacturers, there is simply no other option but to create a bespoke product in-house.

At the 24th Annual Pharmig Conference in Nottingham, Dr Tim Sandle and Edel Fitzmaurice chaired a session on industry practices relating to culture media use, with a view to understanding current trends and how they might be changing.

They found that, in the UK, microbiology labs who produce the prepared media they require for their operations in-house are in the minority. The majority of labs outsource all their prepared media. In between are those who opt for a combined approach, with some culture media produced in-house, and some outsourced.

There is usually a very good reason for media to be prepared in-house, rather than mere preference. For example, the media is quite often unique, designed to individual product specifications, and therefore historically it has not been available from a prepared media manufacturer.

However, a quick overview of the industry clearly shows that many laboratories are now choosing to acquire their prepared media from a manufacturer. While specific types of media often continue to be prepared in-house, external manufacturers are increasingly used to source more generic types.

Laboratories that make some of their prepared media in-house often do so to mitigate the costs involved in sourcing external manufacturers. Other concerns include the issues around sterility and the short shelf life of some specialist media. However, these concerns are being addressed by prepared media manufacturers who offer a broad range of services to meet the needs of every laboratory, whatever mixture of media they require.

Here are the main pros and cons regarding in-house or external suppliers:

Finding cost effective solutions

The main advantage that often drives the idea of in-house prepared media manufacture is that the product is readily available, as and when it is needed. This ‘on demand’ availability together with a perceived cost savings makes a strong case – at least from a high-level view. But how much money are you really saving when you need specific facilities, equipment and resources to achieve superior prepared media for use?

In fact, delay in availability is the only potential disadvantage to sourcing prepared media from an external supplier. Even this should diminish over time as your relationship with the supplier builds and they get to know your average requirement levels. If cost is believed to be an obstacle, it is important to conduct a real audit of your facilities, where all costs related to media manufacture are included. Only once you have a clear picture of both direct and indirect costs of manufacture can you make an informed comparison of in-house versus external production.

In addition, consider the service an external manufacturer can provide. Cost is not only about money spent, but also about the value such a service can bring. A good external supplier will be responsible for the quality of the product you receive. They must carry certain certifications to meet stringent production and storage standards. Once you tally up all the extras you receive from a good supplier relationship, the costs can start to look very different.


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Bespoke media formulation needs, modified packaging needs and suppliers willing to fill small consignments

High standards of product was the reason so many of the participants from the Pharmig Conference choose to, at least in part, outsource their prepared media.

If an obstacle exists to all laboratories being able to do this, it is usually that they may only require media in small batches, which can be difficult to negotiate in a way that makes economic sense. There might also be the question of bespoke media requirements, which in turn necessitate modified packaging.

Many laboratories will spend time, money and resources on building the infrastructure necessary to manufacture their own media in-house so they can fulfil their unique needs. However, a good supplier can quickly and easily meet small consignment needs, will create modified packaging and can tweak formulations to meet the customer’s expectations.

Does your business model and infrastructure support in-house production?

To manufacture prepared media in-house you need to either set up a facility or refurbish and upgrade a current facility. You will need to employ specialised staff members and have the correct validation processes in place. Your facility must remain competent within regulatory guidelines and keep updated with the required certification, at all times.

You will be sourcing basic ingredients to create the prepared media which means coordinating various contacts and keeping up-to-date with your inventory. In-house prepared media manufacturing must operate as a fully-fledged department within your operation. You will need to be in control of, and accountable for, all quality assurance of your media, ensure correct packaging and make sure the end product is validated for the duration of the media’s shelf-life.

Compare managing this complicated, expensive resource with having your prepared media delivered, with full certification of quality control directly to your premises when you need it.

How easily can you access raw materials?

To access the raw materials you require for in-house media manufacture, you will need a collection of contact points that can source materials for you. You may need to purchase materials in bulk if a small consignment is not available and then, you will have to be able to store them. You will need to cultivate a robust supply chain management system for monitoring the shelf-life, validation and sterility of the materials at the various different stages from raw to prepared. This is not unlike the process an external manufacturer will follow to supply their customers. 

At Cherwell, for instance, we take into consideration how readily available the raw materials are and assess all potential risks of the production process, especially where new chemicals are involved. If there are chemicals which we feel are not safe to handle we will refuse to use them. Fortunately, this rarely happens. The same goes with certain pathogens required for growth promotion testing.

Can your processes and resources support adequate QC?

In-house media manufacture requires parameters or checkpoints to ensure quality control (QC). Raw materials guidelines, sterilisation techniques, physicality of all the media types, productivity ratios and contamination parameters must all be in place to ensure what you produce adheres to QC regulations and guidelines.

Using Cherwell as an example again, once we have agreed to create the product needed to the predetermined specifications, we cost the product, create a specification sheet and a QC test sheet. If our team is unfamiliar with the product you require, a trial batch is created so we can gather information on its behaviour to see how it performs with the specified QC testing. Our quality assurance team will ensure precise paperwork and assign a shelf life. Only once the product is considered of premium quality and that it adequately meets our customer’s needs will it be approved for full production.

The end-product is only one part of manufacture of prepared media

Pre-prepared media from a supplier can offer a number of guarantees, such as increased consistency and quality of products. Testing and validation activities are a part of the deal and aligned to industry regulations. The prepared media you receive from your supplier has been validated for specified storage and undergone stability studies for the duration of its shelf-life. Also, a premium external supplier of prepared media can offer you a far wider range of products than you could hope to make in-house.

At the time of writing this article Cherwell Laboratories has 1058 active products on our master list. Our advanced facilities allow us to offer bespoke solutions in consignments of various sizes and we have extensive experience in developing new products. To further understand the ongoing debate around in-house manufactured prepared media versus external sourcing please download our The Pharmaceutical and Cleanroom’s Industry’s Pocket Guide to Prepared Culture Media.



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