The number of viable microorganisms present in or on a product defines its microbiological quality and safety.

While non-sterile products are not required to be free from all microorganisms, they must be tested for bacterial and fungal counts and the presence of specific pathogens. When manufacturing non-sterile pharmaceutical products, you must prove the absence of harmful pathogens, quantify microbial content accurately, and validate your processes in line with stringent pharmacopoeial standards.

Microbiological examination of non-sterile products is therefore a vital step towards ensuring product quality and regulatory compliance.

Our capabilities

Quantitative testing (microbial enumeration tests) 

Quantitative testing determines the total number of viable microorganisms in or on a product. The aim is to quantify the total viable aerobic microbial count (TAMC) and total yeast and mould count (TYMC) in non-sterile products.

Methods:

• Plate count method is used for counting colony-forming units (CFUs) using agar plates. The number of bacterial or fungal colonies is counted and expressed as CFU for TAMC and TYMC.
• Membrane filtration is used when the product can be filtered and is not suitable for direct plating.

Qualitative testing (test for specified microorganisms)

Qualitative testing confirms the absence of microorganisms (defined by current pharmacopeial procedures) in or on a product. The aim is to ensure that non-sterile products do not contain harmful microorganisms that could pose a risk to patients or compromise product quality.

Target microorganisms

• Staphylococcus aureus
• Pseudomonas aeruginosa
• Escherichia coli
• Salmonella spp
• Candida albicans
• Clostridia (in some cases)

Testing methods

For total aerobic microbial count (TAMC) and total yeast and mould count (TYMC) testing, products are first diluted using a validated neutralising diluent. This step inactivates any preservatives or antimicrobial substances that may interfere with microbial recovery, ensuring accurate enumeration of viable microorganisms.

Samples are then analysed using validated microbiological methods, including pour plate, spread plate, or membrane filtration techniques, as appropriate for the product type and testing requirements.

Testing for specified and objectionable microorganisms
Detection of objectionable and indicator microorganisms is performed using enrichment-based methods designed to maximise recovery of target organisms. Samples are appropriately diluted and enriched either by direct broth enrichment or membrane filtration prior to incubation.

Following enrichment, samples are cultured onto selective media to detect and isolate specific microorganisms.

Confirmation and identification
Where typical or suspect growth is observed, confirmatory testing is performed through sub-culturing onto selective and differential media. Further identification can be carried out using advanced technologies, including Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry (MALDI-TOF) and genetic sequencing, with sequence comparison against the Eurofins IDmyk Comparative Sequence Index for accurate microbial identification.

Products can also able to be tested according to specific customer methods.

Sample requirements

• Validation:  20g or 20ml for each test
• Total aerobic, yeast and mould count: 20g or 20ml
• Bile-tolerant gram negative bacteria count: 10g or 10ml
• Index organisms: 20g or 20ml
• Salmonella: 10g or 10ml
• E.coli: 10g or 10ml

Get in touch

Would you like to find out more about our testing solutions, or do you need tailored analytical support? Contact us today to get in touch with our experts.

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