“Consider, which is more appropriate: inclusion in compendial testing of a firm’s own in-house isolates with “wild-type” characteristics that are specific to that firm’s site, or inclusion of organisms isolated many decades ago from a North Carolina blueberry (Aspergillus brasiliensis [niger] ATCC 16404) or from an outer ear infection (Pseudomonas aeruginosa ATCC 9027) and subcultured innumerable times since?”

Robert Westney

“The Role of In-House Microbial Isolates in Contamination Control”

Contamination Control in Healthcare Product Manufacturing, Volume 1

Parenteral Drug Association

June 2013



The use of in-house (“plant”) isolates in microbiological testing is referenced in a number of FDA warning letters and 483 observations, regulatory guidance documents, compendial chapters, and industry publications. Below are several examples. Click on the category name to jump to its listings.

Compliance Deficiencies

Disinfectant Efficacy Testing

Media Growth Promotion

Method Suitability / Validation

Rapid Microbial Methods



FDA Warning Letter
Novo Nordisk A/S
December 12, 2012
“Your disinfectant qualification document ‘Validation of in-use efficacy of [redacted] on production surfaces’ does not describe specific studies to demonstrate effective recovery of organisms from the goggles.”


FDA Warning Letter
Sanofi Pasteur
July 12, 2012
“Form FDA 483 Observation 2.A [April 10-25, 2012]: Your response states that a supplemental disinfectant efficacy study, using mold spores of in house isolates on various surfaces, will be performed and completed by [redacted].  We suggest that this proposed study be conducted as soon as possible.”


FDA Warning Letter
CP Pharmaceuticals, Ltd.
October 29, 2010
“…your firm does not perform challenge testing to the sterility media with environmental isolates from the environmental monitoring program.”


FDA Warning Letter

Catalent Pharma Solutions
March 28, 2008
“Disinfectant effectiveness studies against representative microorganisms and/or specific in-house isolates were not conducted for cleaning agents used in your facility to disinfect production areas, including aseptic areas.”


FDA Warning Letter
American Pharmaceutical Partners, Inc.
January 11, 2001
“Growth promotion testing performed on media fill vials does not include evidence the media is capable of detecting environmental isolates found in class 100 filling areas. For example, mold organisms are not used to challenge media, even though mold isolates have been identified in filling room 1.”


FDA Warning Letter
Centocor, Inc.
July 10, 1998
“Growth promotion qualification of the media used for environmental monitoring does not include a challenge with mold isolates.”


FDA Warning Letter

ZLB Central Laboratory
February 24, 1997
“… the growth promotion tests for media used during environmental monitoring did not include the use of the normal microbial flora commonly recovered and isolated from the various production and support areas.”

“… the study used to support the effectiveness of the cleaning and disinfection solutions is incomplete in that not all of the challenge microorganisms were identified and did not include the use of contaminants that are commonly recovered from the manufacturing areas.”


FDA 483 Observation
Jubilant HollisterStier, LLC
April 14, 2014

In-house environmental isolates are not routinely included in the media fill growth promotion of Soybean Casein Digest (SCD) broth…”

In-house environmental isolates were not included in the growth promotion of TSA-32ml and TSA-80 [redacted] plates.”


FDA 483 Observation
Hospira, Inc.
March 1, 2013
“The validation study to evaluate sanitizers … is inadequate in that … corporate studies did not evaluate isolates from the Rocky Mount site.”


FDA 483 Observation
Central Admixture Pharmacy Services
February 19, 2013
“The firm has not evaluated if their current cleaning and sanitizing methods/practices are effective against in house isolates…”


FDA 483 Observation

Hospira, Inc.

August 24, 2012

Environmental isolates used during growth promotion testing of prepared and purchased media only include gram positive organisms for growth promotion purposes. Environmental isolates do not include gram negative organisms, molds, and yeasts.”


FDA 483 Observation

Alexion Pharmaceuticals, Inc.
August 6, 2012
“The procedure ‘Quality Control of Microbiological Media’ … does not specifically describe how to select environmental isolates to be used in growth promotion.”


FDA 483 Observation
Ben Venue Laboratories, Inc.
May 25, 2011
“The firm was unable to provide scientific rationale for the use of the selected organisms used in the Disinfectant Efficacy study. These organisms were not representative of organisms isolated from the facility nor were they representative of the USP guidelines.”


FDA 483 Observation
McNeil Consumer Healthcare
April 30, 2010
“… the firm does not test TSA…during growth promotion tests for microorganisms to include for example, molds, yeasts and other potential known environmental contaminants found in the manufacturing facility and/or raw materials.”


FDA 483 Observation

CSL Biotherapies, Victoria, Australia
May 2008
Growth promotion studies for purchased and in-house growth media were deficient because there was “no inclusion of environmental isolates in the growth promotions that are conducted, including growth promotion studies for aseptic media simulations”.


FDA Establishment Inspection Report

Alliance Medical Products, Inc.

April-May 2017

“The current EI revealed the following serious cGMP deficiencies… 1. Failure to include an in-house environmental isolate during growth promotion testing of tryptic soy broth used in aseptic media fills…”

Center for Biologics Evaluation and Research
Food and Drug Administration
Administrative File, STN 125389, IGIV (Human)
April 26, 2012
“The section for aseptic process simulation … lacks sufficient narrative to allow a complete evaluation of the process.  … Include in your response the identification of what rooms are covered by the media fills and whether any facility isolates were used during growth promotion testing.”

Review Memo – Biotest Pharmaceuticals Corporation BLA

Food and Drug Administration

August 19, 2011

“The section for aseptic process simulation … lacks sufficient narrative to allow a complete evaluation of the process. … Include in your response the identification of what rooms are covered by the media fills and whether any facility isolates were used during growth promotion testing.”


FDA Pre-BLA Meeting
December 22, 2010
Regarding sterility test method validation: “We recommend the inclusion of facility isolates, such as those recovered from your environmental monitoring.”


FDA Memorandum

Review of Biologics License Application
Institute Bioclon, S.A. de C.V.

January 2009
Regarding Disinfectant Effectiveness Studies: “No rationale was provided for the ATCC organisms used nor was [sic] actual EM isolates used for the study.”


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Questions and Answers on Current Good Manufacturing Practices, Good Guidance Practices, Level 2 Guidance – Control of Components and Drug Product Containers and Closures
Food and Drug Administration
July 5, 2011

“Designing an effective cleaning program involves … selecting the right disinfecting agents to inactivate isolates that may be in the product or in the environment.”


Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing – Current Good Manufacturing Practice

Food and Drug Administration
September 2004
“Routinely used disinfectants should be effective against the normal microbial vegetative flora recovered from the facility… If indicated, microorganisms associated with adverse trends can be investigated as to their sensitivity to the disinfectants employed in the cleanroom in which the organisms were isolated.”


Review Memo – Hiberix

Food and Drug Administration

August 5, 2009

“Validations demonstrated the agent in solution or on surface has a bactericidal, fungicidal, sporicidal or viricidal effect when in contact with predefined organisms (USP microorganisms and In House Isolates or process microorganisms).”


United States Pharmacopeia (USP)

<1072> Disinfectant and Antiseptics

“… the most frequently isolated microorganisms from an environmental monitoring program may be periodically subjected to use-dilution testing with the agents used in the disinfection program to confirm their susceptibility, as there are real differences among different species in resistance to the lethal effects of different sanitizers.”

“To demonstrate the efficacy of a disinfectant within a pharmaceutical manufacturing environment, it may be deemed necessary to conduct the following tests: (1) use-dilution tests (screening disinfectants for their efficacy at various concentrations and contact times against a wide range of standard test organisms and environmental isolates); (2) surface challenge tests (using standard test microorganisms and microorganisms that are typical environmental isolates, applying disinfectants to surfaces at the selected use concentration with a specified contact time, and determining the log reduction of the challenge microorganisms); and (3) a statistical comparison of the frequency of isolation and numbers of microorganisms isolated prior to and after the implementation of a new disinfectant.”

“Regulatory Aspects Concerning the Quality Controls of Microbiological and Nonviable Particulate Contamination in Pharmaceutical Manufacturing”
Ray T. Oji
Food and Drug Administration
American Pharmaceutical Review
January/February 2004
“If using an Association of Official Analytical Chemists (AOAC) method, microorganisms specified in the reference which are most likely to be found in the manufacturing environment should be used and tests performed on microbial isolates frequently found in the environment can provide additional information on the effectiveness of disinfectants.”

Technical Report No. 70: Fundamental of Cleaning and Disinfection Programs for Aseptic Manufacturing Facilities

Parenteral Drug Association


“Recoveries of microorganisms from environmental monitoring samples should be identified to genus and species level when exceeding alert or action levels, and periodically when limits are not exceeded.  Organism identifications should be evaluated to determine the most frequently occurring organisms.  Representative organisms should be preserved and included in the panel of organisms in efficacy testing of antimicrobial agents used in the facility”.


Technical Report No. 13: Fundamentals of an Environmental Monitoring Program (revised)
Parenteral Drug Association
June 2014
“It is recommended to periodically review challenge testing of the selected sanitizers, disinfectants, and sporicides if representative new isolates are routinely recovered in the environmental monitoring program.  This supports the effectiveness of the sanitizer, disinfectant, or sporicide on new contaminants discovered in operations.”


ASTM E2614 – 08 Standard Guide for Evaluation of Cleanroom Disinfectants

ASTM International
“Regulatory authorities now expect evidence of the efficacy of disinfection agents against environmental isolates.”


Center for Biologics Evaluation and Research
Food and Drug Administration
Administrative Files; STN 125363/0
Review of GSK’s BLA
June 12, 2010
“All of the validations noted above met the acceptance criteria specific for each disinfectant’s contact time. Standard USP microorganisms as well as in-house isolates were used as challenges.”


“Disinfectant Efficacy: How Can We Make It Effective?”
Ratul Saha, PhD
American Pharmaceutical Review
August 28, 2019

“The panel of microorganisms selected for the DE study plays a very critical role in assessing the efficacy of the disinfectant. Apart from using standard AOAC challenge organisms, the value is in using typical environmental/facility isolates.”

“Assessment of the disinfection of impaction air sampler heads using 70% IPA, as part of cleanroom environmental monitoring”

Tim Sandle and Ravikrishna Satyada

European Journal of Parenteral & Pharmaceutical Sciences
November 2015

“Similar levels of recovery of the challenge organisms were observed across the three time points. While this part of the study was satisfactory and the results consistent, further studies could be attempted using more environmental isolates.”


“Disinfection Qualification Testing — Considerations for the Aseptic and Cleanroom Manufacturing Environment”

ATS Labs

Dave Rottjakob, M.T. (ASCP)

December, 2013

“A disinfectant product that has a standard label claim for efficacy … does not often demonstrate the same level of efficacy on other surface types against the specific environmental isolates found in the manufacturing environment.”


“Surface challenge testing to qualify disinfectants including sporicides for control of bioburden on production facility surfaces”
Anne Cornish Frazer, PhD
OMICS Group, 2nd International Summit on GMP, GCP & Quality Control
November 12-14, 2013
“In such surface challenge testing, it is desirable to include in-house environmental isolates and demonstrate that cleanroom disinfectants have key performance characteristics…”


“The Antimicrobial Efficacy Test, GMP and Investigations”
Scott Sutton, Ph.D.
American Pharmaceutical Review
August 21, 2013

“… approximately 37% of the respondents were using additional organisms in the AET. These respondents cited environment monitoring isolates and isolates from products as the sources of the additional organisms.”


“Disinfectant Efficacy Testing for Critical Environments”
Marc Rogers, PhD
Steris Life Sciences
PDA SE Chapter
April 18, 2013
“USP (ATCC or USDA) challenge organisms may also be considered but environmental isolates are the most critical.”


“Ensuring Contamination Control”

Dr. Tim Sandle
European Medical Hygiene
November 2012
“In addition to the standard, it would seem that many regulatory inspectors would expect the inclusion of environmental isolates found from the manufacturing environment.”

“The microbiologist will also consider the inclusion of environmental isolates and spore bearing microorganisms – arguments as to when an environmental isolate becomes a ‘laboratory culture’ and problems in creating adequate spore suspensions notwithstanding.”

“When unusual [facility] isolates are recovered, or where there is repeated isolation of theoretically more resistant microorganisms …, it may be prudent to challenge such isolates against one or more of the disinfectant test methods outlined in this article.”


“The Contamination Control Plan in Facility Validation”

Scott Sutton, Ph.D.
Journal of Validation Technology
Spring 2012

“The [contamination control] plan should ideally describe the in vitro or laboratory tests to evaluate the sanitizers, including the identification of the most resistant microorganisms found in the facility … “

“The efficacy of the sanitizers and sporicides used in the program must be demonstrated in a study designed to test their efficacy … against resident microorganisms found in the facilities … “


“In vitro Antifungal Efficacy of Biguanides and Quaternary Ammonium Compounds against Cleanroom Fungal Isolates”

Vijayakumar, R., Kannan, V.V., Sandle, T., and Manoharan, C.
PDA Journal of Pharmaceutical Science and Technology
May/June 2012
“This study clearly demonstrates that the most frequently isolated microorganisms from an environmental monitoring program may be periodically subjected to microbroth dilution testing with cleanroom disinfectant agents used in the disinfection program to confirm their sensitivity profile.”


“Cleanroom Cleaning and Disinfection: Eight Steps for Success”

Dr. Tim Sandle
Controlled Environments Magazine
March 2012
“Disinfectant testing involves challenging the disinfectant solution (as a suspension test) and challenging different surface materials with disinfectant and a range of different microorganisms including isolates from the facility.”


“Contamination Control in the Compliance Program”

Scott Sutton, Ph.D.

Journal of GXP Compliance
Autumn 2011 Volume 15 Number 4

“The efficacy of the sanitizers and sporicides used in the program must be demonstrated in a study designed to test their efficacy … against resident microorganisms found in the facilities …”


“Pharmaceutical Company Jelfa SA (Poland) Receives Warning Letter (7/14/11) Part II”

Barry A. Friedman, PhD LLC
Blog (
August 15, 2011
“Disinfectant Efficacy Studies should be considered as a fundamental requirement during the development of Qualifications of disinfectants on various surfaces with both ATCC and in-house isolates.”


“Prevention of Microbial Contamination”

Elaine Kopis Sartain, Jim Polarine
Pharmaceutical Technology
June 2, 2011
“…scientifically-based references and conventional wisdom used to select these products does not alleviate drug manufacturers of the requirement to validate disinfectants, sporicides, and even isopropyl alcohol for use in facilities under actual use conditions against environmental isolates.”


“Six Steps to Qualifying Disinfectants”

Deborah Ensign, Supervisor, Research and Development
Microtest Laboratories, Inc.
“Determine the Challenge Organisms: Typically, standard American Type Culture Collection (ATCC) test organisms representing the basic classes of microorganisms … along with actual environmental isolates from the client’s facility should be used in the qualification.”


“Evaluating the Activity of Disinfectants Against Fungi”

Jim Polarine, Jr., John Macauley, Peter Karanja, Dan Klein, and Abigail Martin, STERIS Corp.
Volume 23, No. 2, February 2009
“…it is crucial to make an educated investment in antimicrobial products that are effective against your specific mold isolates.”


“Microbial Limit and Bioburden Tests: Validation Approaches and Global Requirements”

Second Edition
Lucia Clontz
CRC Press, Oct 14, 2008
“… users are expected to challenge disinfectants not only with standard test organisms but also with facility environmental isolates because commercially available microorganisms behave quite differently from their ‘wild’ counterparts.  Selection of the test organisms is crucial and an important issue to the regulatory agencies, especially when it comes to environmental isolates.”


“Control Strategies for Fungal Contamination in Cleanrooms”

Paul Lopolito, Carol Bartnett, Jim Polarine
Controlled Environments Magazine
September 2007
“It is generally recommended to use fungal spore suspensions of both reference cultures and environmental isolates … Regulatory authorities also expect to see the specific environmental isolates most frequently found in the facility included in the disinfectant effectiveness testing.”


“Issues That Can Affect The Accuracy Of Environmental Monitoring Data”
Francesco Boschi, Ph.D., Institute of Validation Technology
Journal of GXP Compliance
October 2006

“…assessing the normal flora can help in identifying the most significant and representative strains to be used for: growth promotion testing of media for EM and media fills, validation of disinfectants, and the validation of sterility tests and other lab methods.”


“Surface Disinfectant Validations”

Nelson Laboratories, Inc.
Business Briefing: Medical Device Manufacturing & Technology
“Validation of sanitising agents for effectiveness against isolated organisms found in cleanroom environments is increasingly becoming an area of concern to both manufacturers and regulatory agencies.”

“Disinfectant Validation”
Darren Wallis, GlaxoSmithKline
American Pharmaceutical Review
[unknown publish date]
“Disinfectant validation involves the documented verification and implementation of procedures that have been shown to achieve adequate control over the range and levels of microorganisms that may be encountered in a facility.”

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United States Pharmacopeia (USP)

<1117> Microbiological Best Laboratory Practices

“… microorganisms used in growth-promotion testing may be based on the manufacturer’s recommendation for a particular medium, or may include representative environmental isolates (but these latter are not to be construed as compendial requirements).”

United States Pharmacopeia (USP)

<1116> Microbiological Evaluation of Clean Rooms and Other Controlled Environments
“… for the Growth Promotion test, representative microflora isolated from the controlled environment or ATCC strain preparations of these isolates may also be used to test media.”


Compliance Program Guidance Manual

Program 7356.002A, Sterile Drug Inspections

Food and Drug Administration

September 11, 2015

“The inspection of microbiology laboratory should evaluate the following: … Microorganisms (e.g., ATCC) are used for growth promotion tests of media. Organisms isolated from environmental monitoring samples can also be used to perform growth promotion test.”


Guide to Inspections of Microbiological Pharmaceutical Quality Control Laboratories
Food and Drug Administration
July 1993
“Good practice includes the periodic challenge of prepared media with low levels of organisms. This includes USP indicator organisms as well as normal flora.”


Environmental Monitoring of Clean Rooms in Vaccine Manufacturing Facilities
World Health Organization
November 2012
“Each aseptic manufacturer should consistently evaluate the growth promotion properties of media for a predefined list of organisms… This standardized list should include compendial organisms and/or environmental isolates …”

Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing – Current Good Manufacturing Practice

Food and Drug Administration
September 2004
“The QC laboratory should determine if USP indicator organisms sufficiently represent production-related isolates. Environmental monitoring and sterility test isolates can be substituted (as appropriate) or added to the growth promotion challenge.”


Recommendation on the Validation of Aseptic Processes

Pharmaceutical Inspection Convention / Pharmaceutical Inspection Cooperation Scheme (PIC/S)

1 January 2011

“Selection of [Process Simulation] Growth Medium … The medium selected should be capable of supporting a wide range of microorganisms, which might reasonably be encountered and be based also on the in house flora (e.g. isolates from monitoring etc.).”


Recommendation on Sterility Testing

Pharmaceutical Inspection Convention / Pharmaceutical Inspection Cooperation Scheme (PIC/S)

25 September 2007
“Growth promotion test: … Environmental or fastidious organisms may be used if alternative non-selective enrichment media have been selected for the sterility test.”


Technical Report No. 22: Process Simulation for Aseptically Filled Products

Parenteral Drug Association
December 2011
“The growth promotion properties of the incubation media should be evaluated using pharmacopeial methods. The inclusions of tests for environmental organisms or those isolated from sterility test positives are recommended.”


“Growth promotion testing … is performed using pharmacopeial methods. Consideration should be given to testing with other microorganisms found in the aseptic processing area environment, such as those isolated during environmental and personnel monitoring and sterility test contaminants.”


FDA Establishment Inspection Report
Meridian Medical Technologies (a Pfizer company)
Brentwood, MO
January-February 2012
“The firm uses the specified USP organisms and an in-house environmental isolate. Growth promotion of sterility test media was reviewed and no deficiencies noted.”


BLA Recommendation (FDA)
CSL Behring
January 16, 2009
Regarding growth promotion of media used for media fills: “Growth promotion studies were conducted successfully using indicator microorganisms per USP as well as local isolates.”


“Assessment of Culture Media in Pharmaceutical Microbiology”

Dr. Tim Sandle

American Pharmaceutical Review

June 18, 2014

“In addition to type cultures, environmental isolates are commonly used in media testing regimes. These organisms are designed to demonstrate that a particular lot of culture media will grow microorganisms which are representative of the types that are found in the manufacturing environment.”


“Justification of Incubation Conditions Used for Environmental Monitoring”
Jeanne Moldenhauer, Ph.D.
American Pharmaceutical Review
April 2014
“Test organisms should include both laboratory stock cultures and environmental isolates from the facility.”

“Some companies choose to include more organisms of a specific type that they routinely find in their environment, or have been associated with adverse trends or sterility failures.”


“Microbiological Control of Isolators and Cleanrooms: How to Validate the Use of a New Plate”
Post-Webinar Q and A Session
John Cobb and Colin Booth
May 21, 2014
Q: What is the benefit of using your local isolate in growth promotion tests, since this isolate might be different from the ones isolated by the customer?
A: The normal range of pharmacopoeial/lab strain control organisms allows us to compare different batches with control plates, to check performance is within specification. If wild type isolates from your own EM studies are included in your test panel, I think it gives more credibility to your performance testing. The inclusion of wild type organisms by pharma companies is pretty much a requirement sought after by inspectors these days.


“Microbiology in Filling and Sterility Test Isolators”
Christian Vogt, Alexandra Stärk
American Pharmaceutical Review
March 30, 2012

“The growth promoting properties of a nutrient media batch has to be checked batchwise and preferably including in-house isolates.”


“Microbiological Best Laboratory Practices, USP <1117> Value and Recent Changes to a Guidance of Quality Laboratory Practices”
Scott Sutton, Ph.D., Donald C. Singer
American Pharmaceutical Review
May 1, 2011
“To clarify how selection is determined, a statement was rewritten to indicate relevance, use and selection of the growth promotion microorganisms, in particular environmental isolates.”


Sterile Drug Products: Formulation, Packaging, Manufacturing and Quality
First Edition
Michael J. Akers
CRC Pres
August 20, 2010
“The culture media used for each media fill exercise must be tested to ensure that it will support the growth of microorganisms if they are present.  Challenge organisms used in the media challenge pre-testing should include those isolated from environmental/personnel monitoring, those isolated from positive sterility test results, and USP growth promotion microorganisms”.


“Aseptic Process Simulation”
Ed White
Journal of Validation Technology
Winter 2010
“The first step in an aseptic process simulation is preparing the growth media. This is typically soybean casein digest medium (SCDM) … you will have to perform growth promotion studies on your growth media with your environmental isolates as well as standard growth promotion organisms”.


Validation of Pharmaceutical Processes, Third Edition

James P. Agallaco, Frederick Carleton

CRC Press

September 25, 2007

“The growth promotion test used in the USP Sterility Test is an example of validation of media … Often, environmental isolates can be included in a growth promotion test, or microorganisms isolated from positive sterility tests are also used.”

“Many companies routinely include randomly selected environmental isolates in the growth promotion/support tests prior to release for use.”


“Issues That Can Affect The Accuracy Of Environmental Monitoring Data”

Francesco Boschi, Ph.D., Institute of Validation Technology

Journal of GXP Compliance

October 2006

“…assessing the normal flora can help in identifying the most significant and representative strains to be used for: growth promotion testing of media for EM and media fills, validation of disinfectants, and the validation of sterility tests and other lab methods.”


“Quality Control of Microbiological Culture Media”

Scott Sutton, Ph.D.
Pharmaceutical Microbiology Forum Newsletter
Volume 12, Number 1
January, 2006
“In addition to the compendial organisms required in the [media growth promotion] tests, addition of specific microorganisms of interest could be useful if they have been recovered from past tests (e.g. a Sterility Test contaminant or a frequent environmental monitoring isolate).”


“Introduction to Sterility Testing: Control of the Environment, Test Limitations, and Investigating Manufacturing Systems”

Deborah E. Mentel, Pfizer Global Research & Development
American Pharmaceutical Review
Jan/Feb 2006
“The media must be challenged with the organisms listed in the current version of the compendia as well as one or more in-house isolates … The in-house cultures used must be qualified as well, with regards to identity and population size. The challenge should be with <100 CFU and the population size must be verified and recorded.”


Environmental Monitoring for Cleanrooms and Controlled Environments

Anne Marie Dixon (Editor)
November 2, 2006.
Informa Healthcare. First Edition.
“Media Growth Promotion: In general, a microbial growth medium such as soybean casein digest medium should be used. This media selected should be demonstrated to promote growth of United States Pharmacopoeia (USP) <71> indicated organisms as well as representative isolates identified from environmental monitoring, personal monitoring, and positive sterility test results.”


“Microbial Testing in Support of Aseptic Processing”

Anthony M. Cundell, Ph.D.
Pharmaceutical Technology
June 2004
“Growth promotion should be demonstrated using organisms listed in USP General Chapter <71> as well as environmental, personnel, and sterility test failure isolates [at the] <100-cfu challenge.”

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Final Rule: Amendments to Sterility Test Requirements for Biological Products

Food and Drug Administration
June 4, 2012
Regarding sterility test method validation: “The test organisms selected should reflect organisms that could be found in the product, process, or manufacturing environment.”


“Use of Stressed Populations for Application Validation to Better Represent Real World Testing”
Andrew Sage, Ph.D.
American Pharmaceutical Review
August 31, 2013

“Model stressed populations should reflect the bioburden of the sample, and mimic exposure to the stress factors that are present in the sample matrix as closely as possible. in order to achieve this, the isolates obtained from the sample environment should be identified and used.”


“The Use of Environmental Isolates”

Tim Sandle, Ph.D.
Pharmaceutical Microbiology Blog
January 10, 2010
“There is a strong argument that environmental isolates are the best challenge to media and for validation studies like sterility test validation. They are the most sensitive micro-organisms, having been exposed recently to disinfectants, particular soils etc.”


“Bioburden Method Suitability for Cleaning and Sanitation Monitoring: How Far Do We Have to Go?”

Angel L. Salaman-Byron
Pharmaceutical Technology
August 2, 2010
“The author highly suggests performing test method suitability studies using wild-type isolates from production surfaces instead of laboratory-adapted strains of bacteria. Wild-type strains are a better representation of the organisms encountered on production areas than those strains that lack wild characteristics.”


“Microbiological Quality of Drug Products after Penetration of the Container System for Dose Preparation Prior to Patient Administration”
John W. Metcalfe, Ph.D.
American Pharmaceutical Review
February 1, 2009
“We suggest that the [product growth promotion] challenge microbes include the panel provided in USP<51>, as well as typical skin microflora and nosocomial agents to simulate the types of flora that may contaminate a drug product in a hospital pharmacy.”


“Issues That Can Affect The Accuracy Of Environmental Monitoring Data”

Francesco Boschi, Ph.D., Institute of Validation Technology

Journal of GXP Compliance

October 2006

“…assessing the normal flora can help in identifying the most significant and representative strains to be used for: growth promotion testing of media for EM and media fills, validation of disinfectants, and the validation of sterility tests and other lab methods.”

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Guidance for Industry: Validation of Growth-Based Rapid Microbiological Methods for Sterility Testing of Cellular and Gene Therapy Products (Withdrawn)

Food and Drug Administration
Center for Biologics Evaluation and Research
February 2008
“You should develop a panel of microorganisms relevant to the product and process to challenge the performance of your RMM. We recommend that you include in your panel microorganisms which represent the following categories:

– isolates detected in starting materials

– isolates detected by in-process testing or during preliminary product testing

– isolates detected by environmental monitoring of your manufacturing facility

– isolates from your production areas which represent low nutrient and high stress environments … “


“Validation of Growth Direct Applications: EM and Sterility Testing”
The Rapid Blog & News
Rapid Micro Biosystems
December 5, 2013
“Time-to-Result (TTR) Selection: During performance qualification (PQ), users select their TTRs based on a suite of microorganisms commonly found in their clean rooms, environmental isolates and stressed organisms”.


“Revision of PDA Technical Report Number 33”

Michael J. Miller and Jeanne Moldenhauer
American Pharmaceutical Review.
February 1, 2010
Issue 13, Volume 1

“Additional considerations [for RMM validation] may be provided with regard to … environmental isolates.”

“Automated Rapid Microbiological Methods for the Biopharmaceutical Industry: Selection, Validation, and Implementation for an Autologous Cell Therapy Product”
John Duguid & Gary C. du Moulin Ph.D., Quality Systems, Genzyme
American Pharmaceutical Review
June 2009
“Validation studies evaluated sterility test samples from primary culture, expansion culture, and final product culture with a microbial challenge comprised of 10 microbial species. These species included a mix of commercial reference strains and stressed cells from frozen archives of environmental isolates and sterility test failures. During the validation process, FDA recommended challenge microorganisms …”

“The Introduction of Qualitative Rapid Microbiological Methods for Drug-Product Testing”

Paul Newby, Gilberto Dalmaso, Silvano Lonardi, Bryan Riley, Peter Cooney, and Kim Tyndall
Pharmaceutical Technology, Process Analytical Technology
“To demonstrate the [RMM’s] ability to detect a range of microorganisms, at least six replicate samples of drug product were spiked with 10 to 100 cfu of microorganisms from site-specific isolates and … compendial microorganisms …”

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