Traditional & Rapid Sterility Testing
The right sterility pathway for every product line.
Sterility testing is not one-size-fits-all. PlumGXP combines traditional compendial testing with two rapid sterility options so the method can be selected around the product, matrix, manufacturing process, release needs and intended use of the result.
- USP <71> traditional testing
- Two rapid sterility options
- Product-specific validation
Three testing pathways
Choose based on product fit—not platform limitations.
PlumGXP evaluates the product and program before recommending a pathway. Traditional testing remains the compendial foundation, while two rapid options can support faster decisions when the method is appropriately validated for the intended application.
Traditional Sterility
Membrane filtration or direct inoculation selected according to the product, test requirements and method-suitability results.
- USP <71> and applicable compendial methods
- 14-day incubation
- Bacteriostasis and fungistasis testing
- Established pathway for varied product types
Rapid Sterility Pathway One
A validated alternative selected when its detection approach, sample requirements and product compatibility align with the client’s application.
- Faster information for time-sensitive programs
- Product- and matrix-specific validation
- Defined equivalence or comparability strategy
- Investigation pathway considered in advance
Rapid Sterility Pathway Two
An additional rapid option expands the range of products, matrices and operational needs that can be evaluated without relying on one rapid platform.
- Alternative product-fit profile
- Additional capacity and scheduling flexibility
- Contingency for platform-specific limitations
- Validation aligned with intended use
One manufacturer may need more than one sterility method.
An aqueous injectable, oil-based formulation, biologic, preservative-containing product and medical device may not behave the same way in a sterility method. Multiple platforms allow different product families to follow the pathway that provides the strongest scientific and operational fit while remaining within one laboratory relationship.
Traditional sterility testing
Controlled execution in an ISO-classified environment.
Traditional sterility testing is performed within an ISO 7 cleanroom under ISO 5 conditions. Based on product characteristics and applicable requirements, testing is performed by membrane filtration or direct inoculation.
For filterable products, PlumGXP uses the Sartorius Sterisart closed filtration system. The closed pathway helps reduce open manipulations during filtration, rinsing and incubation, adding another layer of contamination control to the test process.
- Membrane filtration
- Direct inoculation
- Fluid thioglycollate medium
- Soybean-casein digest medium
- Defined incubation conditions
- Documented observation and review
Method qualification & validation
Before routine results can be trusted, the method must work with the product.
PlumGXP develops a product-specific study strategy based on the selected sterility pathway, product matrix, intended use and applicable regulatory market.
Traditional method-suitability testing demonstrates that the product does not prevent recovery of the required challenge microorganisms under the proposed test conditions.
Rapid-method performance is compared with the compendial method using a predefined, scientifically justified design appropriate to the intended application.
Studies evaluate the method’s ability to detect low levels of microorganisms under defined conditions relevant to sterility testing.
Product characteristics, filtration behavior, background signal, antimicrobial activity and other potential sources of inhibition or interference are evaluated.
The study assesses whether the method produces the intended microbial response and performs consistently across repeated conditions.
Where scientifically appropriate, stressed or injured organisms may be incorporated to challenge recovery under conditions more representative of manufacturing and product exposure.
Validation framework: Study designs may draw upon USP <1223>, Ph. Eur. 5.1.6, PDA Technical Report No. 33 and applicable regulatory expectations. The exact characteristics and acceptance criteria are selected according to the technology, product and intended use. The revised Ph. Eur. 5.1.6 published in Issue 13.2 has an implementation date of April 1, 2027.
Product diversity
A sterility program built around what you manufacture.
The most appropriate method can depend on formulation, sample volume, container, filtration characteristics, antimicrobial activity, background interference, release timeline and the need to recover an organism for identification.
Aqueous Products
Often suitable for filtration, subject to product-specific rinsing and suitability considerations.
Oils & Difficult Matrices
May require tailored preparation, dilution, solubilization or another testing pathway.
Biologics & Advanced Therapies
Limited volume, short shelf life and time-sensitive decisions may materially affect method selection.
Medical Devices
Configuration, extraction, immersion, rinse fluid and product geometry influence the method design.
Why multiple platforms benefit the customer
Instead of transferring different product lines among several laboratories, clients can work with PlumGXP to evaluate a coordinated portfolio strategy. One product may remain on the traditional compendial method while another uses a validated rapid option. This simplifies communication, qualification, program oversight and investigation support while preserving method flexibility.
When detection becomes investigation
A positive signal is the beginning of the question—not the end.
When a microorganism is recovered, identification can help assess what the result may mean and where the investigation should look next. The ability to retain or recover an organism for identification should be considered when selecting a sterility pathway.
- Evaluate potential associations with personnel, environment, water, raw materials or processing
- Compare the recovery with historical environmental or product isolates
- Support risk assessment, targeted resampling and investigation decisions
Program development
From product assessment to routine testing.
- 01 / ASSESS
Understand the product
Review the formulation, manufacturing process, container, sample availability, release needs and testing history.
- 02 / SELECT
Choose the pathway
Determine whether traditional filtration, direct inoculation or a rapid option provides the appropriate fit.
- 03 / VALIDATE
Demonstrate performance
Execute the required suitability, equivalence and product-specific validation studies.
- 04 / IMPLEMENT
Begin routine testing
Establish sample submission, scheduling, reporting, investigation and change-management expectations.
Frequently asked questions
Planning a sterility program?
Does every product need the same sterility method?
No. Product matrix, antimicrobial activity, filtration characteristics, sample volume, container configuration, release timeline and intended market can affect method selection. A portfolio may appropriately use more than one testing pathway.
What is bacteriostasis and fungistasis testing?
B&F testing is the method-suitability evaluation used with traditional sterility testing to demonstrate that the product does not inhibit recovery of the required challenge microorganisms under the proposed test conditions.
Can a rapid sterility method be used without product validation?
A rapid alternative must be supported by a scientifically justified validation and implementation strategy for its intended use. Product-specific suitability, interference and applicable comparability or equivalence expectations must be addressed before routine use.
Why is organism recovery important when selecting a rapid method?
If a test produces a positive result, recovery of the organism can be essential for identification and investigation. The investigation pathway—including how an organism will be recovered and identified—should be considered before selecting and validating the rapid method.
Can PlumGXP help select a method across several product lines?
Yes. PlumGXP can review the portfolio and help develop a product-family strategy that uses traditional or rapid testing according to the needs of each formulation while keeping the program coordinated through one laboratory.
Build a sterility strategy around your products—not one instrument.
Tell us about your formulations, timelines and current testing challenges.