Just a quick question to canvass  opinion;

Currently have a requirement to  conduct suitability testing for sterility  (membrane filtration),  but the Sterility Test Suite is located some distance from the lab facility.  To remediate, logistics / bio-contamination risk issues,  the plan is to conduct  the  "final spiking step"  of the canisters with low level inoculum of the appropriate  type cultures, within the laboratory.

All prior handling steps, decontamination, reconstitution, filtration and  initial rinses  will take place within the qualified Sterility Test Isolator to capture variation during decontamination and handling.

The issue relates to the final inoculation step. Keeping in mind that the harmonised method  for MF refers to
adding  "an inoculum of a small number of viable microorganisms (not more than 100 cfu) to the final portion of the sterile diluent used to rinse the filter".

1)  whether it would be permissible to add the inoculum directly to the media filled canisters (under controlled conditions) or is it the intent that inoculation must occur as part of the final rinse prior to media fill to ensure that all potential  inoculum  / membrane / product residue interactions are captured?

2)  if the intent is such would it be acceptable to firstly conduct a full Suitability Testing  program under controlled lab conditions (i.e. but not employing the actual Sterility Test Isolator or associated equipment) in order to demonstrate recovery (absence of bacteriostasis / fungistasis)  and then run a second series using  the defined equipment (the Sterility Test Isolator) but with the amendment of a final (lab-based)  direct inoculum of the prior processed and  media filled canisters?

Thanking you in advance for your feedback,

Best Regards

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