Bacterial Retention Testing

The bacterial retention test is to confirm the microbial retention ability of the sterilizing filter by simulating the worst-case process parameters after evaluating the actual filtration process in production, and filtering product solutions or product replacement solutions containing a certain amount of challenging microorganisms. Bacterial retention testing ensures that the filter produces a sterile effluent even when loaded with bacteria, making it a critical step in filter validation for biopharmaceutical manufacturers.

During the test, a filter or product is exposed to a suspension of a specific type of bacteria, most commonly Brevundimonas diminuta or Escherichia coli. The filtered liquid is then analyzed to determine the number of bacteria that passed through the filter.

STEMart provides comprehensive and reliable bacterial retention testing services to evaluate the filtration efficiency of products such as filters, pharmaceuticals, and medical devices, to ensure they can effectively remove or reduce bacteria.

Test Samples

Medicinal liquid filtration membrane, medicinal liquid filter, air filter, ultrafiltration membrane

Test Steps

• Prepare the bacterial suspension
• Determine the viable cell concentration of bacteria
• Prepare the device
• Conduct the test
• Evaluate the test
• Document the results
  • Identification of the filter (type of filter, manufacturer, batch number, pore size, etc.)
  • Operating conditions (pressure, temperature, flow rate etc.)
  • Concentration of used bacterial suspension
  • Number of colonies on the negative control and the sample
  • Results of the filter integrity test
  • Calculated filter performance (bacterial retention rate)

For more information about our bacterial retention testing services, please contact us.