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Product Sterility – Cleanroom


Cleanroom test being performed at Nelson Labs for product sterility

The Product Sterility Cleanroom Test is necessary for medical devices, pharmaceuticals, preparations, tissue materials and other materials that claim to be sterile or free from viable microorganisms. The cleanroom is a classified space where lab analysts are equipped with special gowns and precautions to not add bioburden to the test area where they perform aseptic manipulations of products to test for sterility. This test is performed according to the recommendations from

  • USP 71
  • USP 161
  • USP 797
  • EP 2.6.1
  • JP 14 54
  • ANSI/AAMI/ISO 11737
  • AAMI TIR33

To optimize aseptic transfer of samples into the test media, all testing is performed in an ISO Class 6 cleanroom. Utilizing advanced technology such as a double airlock system and unidirectional airflow to ensure a sterile work environment. Product sterility cleanroom tests must be validated by performing a Method Suitability (Bacteriostasis/Fungistasis (B/F), Sterility and MPN Method Suitability) test to substantiate the sterility test. Without this validation, it is impossible to verify the sterility of your manufacturing process, as contaminants could be masked by the antimicrobial agents in the product. Method Suitability testing is required by the United States Pharmacopeia (USP) as well as the U.S. Food and Drug Administration (FDA) to safeguard appropriate operating procedures. 

Study Outline

The Product Sterility Cleanroom test evaluates samples for sterility by placing them in growth media, incubating them for a minimum of 14 days, and then checking for evidence of microbial contamination. Similar to our other Product Sterility Isolator test we offer, however the cleanroom tests products that are meeting both USP and AAMI standards.

Samples may be tested using either direct inoculation or membrane filtration, and using a tryptic soy broth (TSM) or fluid thioglycolate media (FTM), as follows:

Direct Inoculation:   

Samples tested by direct inoculation are aseptically immersed in nutritive broth. Incubating the growth medium with a defined quantity of drug product sample. The dilution of product used must be adequate to overcome microbial properties present in the drug product being tested.

Membrane Filtration:

Samples tested by membrane filtration (liquids, filterable solids, soluble oils [oils] and sterile-pathway-only devices) are passed through a 0.45µm filter, and the filter is immersed in the test media.

Tryptic Soy Broth Media:

For Isolator Sterility tests, the USP method calls for a tryptic soy broth media (TSM) for aerobic and fungal growth at incubation temperatures of 20-25°C. For the AAMI method, samples are incubated at temperatures of 28 – 32°C. Sample size is determined both by batch size and individual container fill volumes.

Fluid Thioglycolate Media:

For Isolator Sterility tests, the USP method calls for a fluid thioglycolate media (FTM) used for anaerobic growth at an incubation temperature of 30-35°C. Sample size is determined both by batch size and individual container fill volumes.

After a 14-day incubation, samples are evaluated for the presence of turbidity and/or growth. A media transfer and/or confirmation test may be performed. A failure investigation is performed as necessary. Recovered organisms are identified and compared to the organisms that may have been recovered on monitors performed by the test analyst during applicable test sessions. It is determined whether any anomalies occurred on the day of testing, with media sterilization, during sample processing, and/or during shipping.

Additional Recommended Testing

Method Suitability (Bacteriostasis/Fungistasis) is a required validation needed annually to substantiate a sterility test in confirming that there are no antimicrobial properties present. If changes are made in a pharmaceutical compound, or a new product is needed, It is critical that method suitability testing is done before sterility testing.

Testing Locations

  • Salt Lake City, UT, USA
  • Itasca, IL, USA
  • Rantigny, France
  • Espergaerde, Denmark
  • Wiesbaden, Germany
  • Shanghai, China

Learn more about our locations and their certifications.

Contact Us

If you have additional questions about Product Sterility Cleanroom test services, or would like to consult with the experts at Nelson Labs, just send us a request or call us at +1 (801) 290-7500.