General Microbiology Testing
Q: What types of microbiology testing do you offer?
We support a full range of microbiological testing programs across pharmaceutical, biotechnology, and medical device applications. This includes microbial enumeration (USP <61>), specified organism testing (USP <62> and <60>), sterility testing (USP <71>), endotoxin testing (USP <85>), antimicrobial effectiveness testing (USP <51>), environmental monitoring, and utility microbiology.
We also support more complex programs involving method suitability, inhibition, low recovery, and investigation work.
Q: Do you support both routine testing and investigations?
Yes. We support both routine release/stability testing and technically complex work such as method failures, out-of-specification (OOS) results, and contamination investigations.
Many clients engage us specifically when standard approaches have not produced reliable results.
Q: What industries do you work with?
We primarily support:
- Pharmaceutical manufacturers
- Biotechnology companies
- Medical device manufacturers
- CDMOs and CMOs
- Packaging and material suppliers
Our work is aligned with cGMP-regulated environments and audit expectations.
Method Suitability & Inhibitory Products
Q: What is method suitability and why is it important?
Method suitability is the demonstration that a microbiological method can recover microorganisms in the presence of a specific product. It confirms that the product does not inhibit growth or interfere with detection.
Without demonstrated suitability, results may appear compliant but are not scientifically valid.
Q: What happens if my product is inhibitory?
Inhibitory products can suppress microbial recovery, leading to false negatives. We evaluate inhibition and develop strategies such as neutralization, dilution, filtration, or modified preparation techniques to ensure accurate recovery.
This is one of the most common reasons microbiology methods fail.
Q: Can you help if another lab couldn’t make the method work?
Yes. This is a core part of our work. We are often engaged after repeated method suitability failures, inconsistent recovery, or borderline results.
We approach these cases as technical problems to solve, not just tests to run.
Microbial Enumeration (USP <61>)
Q: What are TAMC and TYMC?
Total Aerobic Microbial Count (TAMC) and Total Yeast and Mold Count (TYMC) are quantitative measures of microbial contamination in a sample. Results are typically reported as CFU per gram or per mL.
Q: Why are my microbial counts lower than expected?
Low counts are often caused by:
- product inhibition
- poor neutralization
- inappropriate diluents
- recovery issues
We evaluate these factors to determine whether results reflect true microbial levels.
Q: Do you support low sample volume testing?
Yes. We have experience developing strategies for small sample sizes, including optimized recovery approaches and sensitivity-focused methods.
Specified Organisms & Bcc (USP <62> / <60>)
Q: What are specified organisms?
Specified organisms are microorganisms that must be absent or controlled depending on product type and route of administration. These include organisms such as E. coli, Salmonella, Pseudomonas aeruginosa, and Staphylococcus aureus.
Q: What is Burkholderia cepacia complex (Bcc) and why is it important?
Bcc is a group of opportunistic pathogens associated with contamination of aqueous and non-sterile products. It is particularly relevant for inhalation products and products used by immunocompromised patients.
USP <60> provides a dedicated method due to the difficulty of detecting Bcc in complex matrices.
Q: Do all products require Bcc testing?
Not all products require it, but it is strongly recommended for aqueous non-sterile products and has been the focus of regulatory scrutiny and product recalls.
Endotoxin Testing (USP <85>)
Q: What is endotoxin testing?
Endotoxin testing detects lipopolysaccharides from gram-negative bacteria, which can cause pyrogenic reactions in patients. It is a critical safety test for parenteral products and medical devices.
Q: What causes endotoxin test interference?
Interference can be caused by product components that inhibit or enhance the LAL reaction. This can lead to false negative or false positive results if not properly addressed.
Q: What is Maximum Valid Dilution (MVD)?
MVD is the highest dilution at which a sample can be tested while still detecting endotoxin at the required limit. It defines the allowable range for overcoming interference without losing sensitivity.
Q: Do you support medical device extraction testing?
Yes. We support fluid path, immersion, and rinse extraction methods for medical devices, with full documentation aligned to regulatory expectations.
Sterility Testing (USP <71>)
Q: What is bacteriostasis and fungistasis (B&F)?
B&F testing demonstrates that a product does not inhibit microbial growth in the sterility test system. It is required to confirm that sterility results are valid.
Q: What causes sterility test failures?
Failures can be caused by:
- true product contamination
- environmental contamination during testing
- laboratory error
We support investigation to determine root cause and appropriate next steps.
Q: Can you support sterility failure investigations?
Yes. We assist with invalidation assessment, organism identification, environmental review, and retest strategy development.
Antimicrobial Effectiveness Testing (USP <51>)
Q: What does AET measure?
AET evaluates whether a product’s preservative system can reduce or control microbial populations over time under defined challenge conditions.
Q: What does it mean if my AET results are borderline?
Borderline results may indicate issues with formulation, preservative concentration, or method suitability. We evaluate whether results reflect true product performance or testing artifacts.
Q: Do you perform disinfectant efficacy studies?
Yes. We support disinfectant efficacy studies for environmental control programs, designed to reflect actual use conditions.
Environmental & Utility Monitoring
Q: What is USP <1116>?
USP <1116> provides guidance on microbiological control of cleanroom environments. It emphasizes trend analysis and maintaining a state of control rather than relying solely on numerical limits.
Q: What should an environmental monitoring program include?
A program should include:
- viable air sampling
- surface monitoring
- personnel monitoring
- trend analysis and defined response procedures
Q: How often should water systems be tested?
Frequency depends on system design, usage, and risk. Routine monitoring typically includes microbial enumeration and endotoxin testing at defined points throughout the system.
Q: Do you support compressed air testing?
Yes. We support viable monitoring of compressed air and process gases, particularly where they contact product or critical surfaces.
Turnaround, Logistics & Working With Us
Q: How quickly can you complete testing?
Turnaround times vary depending on the test and program complexity. We provide clear expectations upfront and support expedited timelines where needed.
Q: Do you offer method development or just testing?
We support both. Many of our engagements involve method development, suitability optimization, or troubleshooting in addition to routine testing.
Q: How do I get started?
Contact us with:
- test type or challenge
- product or sample type
- applicable standards (if known)
- timeline
If you’re unsure, we can help define the right approach.
