Also known as Casein Digest Peptone, TSA is the primary medium used for environmental monitoring applications within pharma because it will grow a wide range of bacteria and mould. Referenced in the pharmacopoeia, TSA is a pale straw-coloured media that is particularly good at withstanding the effects of gamma radiation due to a low content of sugars.
The limits within GMP for viable particles within cleanrooms are all based on the use of TSA in Settle plates and active air samples.
Relevant products:
Gamma Irradiated Media
Poured Culture Media Plates
Relevant content:
Incubating Plates - Challenges and Lessons Learnt
Redipor® Triple Wrap Packaging Illustration
A noticeable development within pharma EM over the last 10 years has been the increasing use of media supplemented with disinfectant neutralisers. The common supplements were Lecithin and Tween, but this has been surpassed by a 4 neutraliser mix which also includes L-Histidine and Sodium Thiosulphate.
Neutralisers are typically used in Contact plates for surface monitoring, but increasingly users have also included them in Settle plates to counteract disinfectant residues from finger dabs.
Relevant products:
Gamma Irradiated Media
Poured Culture Media Plates
Relevant content:
Why Use Neutralisers in your Environmental Monitoring Plates?
Researching Disinfectant Neutralisers
Are all Contact plates the same when it comes to EM?
The main medium for sterility testing, TSB is the liquid version of TSA, mentioned above, with the absence of agar to set the medium. A mid to dark brown liquid it is presented in many different containers, from 5ml Injection vial, to Ampoules and Broth Bags, all to allow users to assess the sterility of a product, process or operator.
As with most liquid growth medium, contamination shows as turbidity of the normally clear liquid.
Relevant products:
Injection Vials and DIN Bottles
Universal Operator Broth Transfer Kit
Bottled Media Products
Broth Bags and Ampoules
Relevant content:
Cherwell to Introduce New Redipor® Broth Kit at APDM
Case Study: Great Ormond Street Hospital (GOSH)
SDA is a mould and fungi specific agar that can be used to supplement EM programs, especially in slightly lower grade facilities where the presence of mould and fungi could be more likely. Sabouraud Dextrose agar is very similar in colour to TSA, so users need to be aware of the risks and implications of mixing the two agar types.
The increasing reliance on dual incubation within pharma EM for TSA has significantly reduced the amount of SDA used.
Relevant products:
Gamma Irradiated Media
Poured Culture Media Plates
Relevant content:
Considerations for Environmental Monitoring Plates
Redipor® Contact Plate Grip Lids Demonstration Video
Also known as FTM, Thioglycollate is a specific growth medium for anaerobic organisms. Its main application is again within sterility testing but specifically to identify anaerobic organisms within a sample or product.
A key performance parameter for FTM is the presence of resazurin, an indicator of aerobic conditions within the medium. This can typically present itself as a shallow pink band at the top of the medium. This doesn’t affect the performance of the medium, and if need be, can be driven off by gently heating the medium.
Relevant products:
Injection Vials and DIN Bottles
Bottled Media Products
Relevant content:
Cherwell provides CMO with bespoke broth for method validation
Prepared Microbiological Media: Pros and cons
This low nutrient medium is designed for the recovery of organisms from water which may have been stressed by water treatment solutions. Proven to be more effective than more nutritious media, this agar is typically incubated at lower temperatures for longer periods to help with recovery of those damaged organisms.
Developed by Reasoner and Geldreich, this pale coloured medium is used to assess the quality of processed water within pharma.
Relevant products:
Relevant content:
How Cherwell ensures consistent quality of all Prepared Media
How to Store Prepared Media Plates 
