Quality Control Specialist | Industry Experience
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📅 Last Updated: October 31, 2026
Media fill acceptance criteria are the pass/fail rules for an aseptic process simulation (APS), fixed in the approved protocol before the run starts. Under EU GMP Annex 1 (2022), the target is zero growth, and any contaminated unit fails the APS. FDA’s 2004 guidance is nonbinding and ties its recommended response to the units filled. No single threshold fits every market or APS design. Your decision follows the regulation that applies to you and your approved protocol, and a failure always needs a documented investigation.
What Are Media Fill Acceptance Criteria?
Media fill acceptance criteria are the rules that decide whether an APS run passed. The site writes and approves them before any unit is filled. For the full overview, see What is media fill in pharmaceutical. This article goes deeper into how the QA officer judges the results.
Fixing the rules first stops anyone bending them after seeing the vials. The protocol carries the units to fill, the incubation, the inspection method and the pass/fail rule. The media fill procedure and protocol guide shows how these parts fit together.
Process design, quality system discipline, training and monitoring data do the main job of validating an aseptic process. APS has a defined role beside them: it periodically verifies that the controls work (Annex 1, 9.32).
Which Media Fill Acceptance Criteria Apply in Your Market?
The answer depends on where you supply. The European Commission states that Annex 1 of EudraLex Volume 4 has been fully applicable since 25 August 2024. PIC/S members use the same revised Annex 1, which entered the PIC/S GMP Guide in PE 009-17 on 25 August 2023. PE 009-18 is the current guide from 24 September 2026.
WHO TRS 1044 Annex 2 (2022) is a text harmonised with these documents.
The US works differently. Manufacturers must have written procedures to prevent microbial contamination of products purporting to be sterile (21 CFR 211.113(b)). The FDA 2004 aseptic processing guidance explains what FDA expects from media fills, as nonbinding recommendations.
| Authority | Document | Rule for contaminated units | Status |
|---|---|---|---|
| EU | Annex 1 (2022), 9.46 | Target zero growth; any contaminated unit fails the APS | Part of EU GMP |
| PIC/S | PE 009-17 (Annex 1); current guide PE 009-18 | Same revised Annex 1 | Applied by member inspectorates |
| WHO | TRS 1044 Annex 2 (2022) | Text harmonised with EU and PIC/S | WHO GMP guidance |
| US | FDA guidance (September 2004) | Response banded by units filled | Nonbinding; CGMP regulations bind |
FDA recommends these responses for assessing line control:
| Units filled | Contaminated units | FDA recommended response |
|---|---|---|
| Fewer than 5,000 | 1 | Revalidation, after investigation |
| 5,000 to 10,000 | 1 | Investigation, including consideration of a repeat media fill |
| 5,000 to 10,000 | 2 | Revalidation, after investigation |
| More than 10,000 | 1 | Investigation |
| More than 10,000 | 2 | Revalidation, after investigation |
FDA also says that contamination in any run, whatever its size, points to a potential sterility assurance problem. A firm stays fully liable for shipping any nonsterile unit, whatever criteria it uses. Your site procedure can be stricter than these texts.
How Do You Evaluate Contaminated, Damaged and Excluded Units?
Count every unit first, then treat each category by the rule. Annex 1 and FDA draw the lines in nearly the same places.
Integral Units and Units Lacking Integrity
You must incubate and evaluate all integral units, meaning units with intact containers. That includes units with cosmetic defects and units that passed non-destructive in-process checks (Annex 1, 9.41). FDA says the same and adds that units lacking integrity are rejected before incubation. If a unit is rejected by mistake, it goes back for incubation with the run.
A unit found damaged after incubation starts stays in the run data. Excluding it needs full justification and an explanation of the deviation in the media fill report (FDA 2004, section IX.A.8).
Discarded Units and Aborted Runs
An APS may remove units without incubating them only as a routine fill would. Production SOPs must call for the same removal for that intervention type, line location and unit count. The APS never removes more than a production run would. For example, say the routine SOP clears 10 units after an intervention at the stoppering station infeed. The APS clears the same 10, and both batch records show it.
Operators usually incubate units cleared during set-up or mandatory line clearance separately. They show set-up risk, so they need not count toward the acceptance criteria. Abort an APS only where written procedures require commercial lots to be handled the same way, and document an investigation (Annex 1, 9.48).
Reconciliation and Unexplained Gaps
A reconciliation is a count that accounts for every unit filled. It covers incubated and non-incubated units, with a justification for each non-incubated unit (Annex 1, 9.47). An unexplained gap means you can’t trust the result, so raise a deviation before accepting any outcome.
What Do Initial and Repeat APS Require?
Annex 1 uses three separate terms: initial validation, periodic revalidation and repeat of the initial validation. Use them as written.
| Item | EU GMP Annex 1 (2022) | FDA 2004 guidance |
|---|---|---|
| Initial | At least three consecutive satisfactory simulations covering all working shifts (9.38) | At least three consecutive separate successful runs at line qualification |
| Routine repeat | Normally twice a year, about every six months, per process, line and shift (9.38) | Semi-annual, per line |
| Personnel | Each operator at least one successful APS yearly (9.38); manual operations need three consecutive initially and about six-monthly repeats (9.39) | Everyone authorised to enter the aseptic room, at least once a year |
| Units filled | Justified in the CCS; typically 5,000 to 10,000 minimum (9.40) | Starting point 5,000 to 10,000 |
| Incubation | Justified and validated conditions and duration (9.44) | Not less than 14 days at 20 to 35 °C, held within ±2.5 °C |
The 14 days and 20 to 35 °C belong to FDA. Annex 1 sets no fixed period, so your protocol states what your site justified. After a long idle period, you repeat the initial validation. You also repeat it after a change that can affect the aseptic process, including new container-closure combinations (Annex 1, 9.49).
Trained, qualified staff inspect the units. Staff inoculate positive-control units with reference organisms and local isolates (9.45). The incubation and inspection guide covers this, and the growth promotion guide covers the medium. The interventions and worst-case design guide covers what the run must challenge.
How Are Media Fill Results Documented and Reviewed by QA?
The APS batch record holds everything (Annex 1, 9.47). It includes the reconciliation and all microbial monitoring data. It also lists each intervention with start time, end time and the person involved. FDA adds that the QC team should observe the run. You must be able to trace contaminated units back to the approximate time and the activity the operators simulated.
The QA officer then reviews the whole package against the predefined criteria. The review checks that reconciliation closes and that qualified inspectors examined the units. It also checks that positive controls grew, monitoring covered the full run and staff raised every deviation. The quality control unit must review production and control records (21 CFR 211.192). The site SOP defines the sign-off steps and deviation class.
Related topic: media fill for powders and lyophilized products
What Must You Do After a Contaminated Unit or a Failed APS?
Any contaminated unit fails the APS. These actions follow:
- Investigate to find the most probable root cause or causes.
- Decide and apply corrective measures.
- Run enough consecutive successful repeat APS, normally a minimum of 3, to show the process is back in control.
- Review promptly all aseptic production records since the last successful APS, with a risk assessment of potential sterile breaches in those batches. Other unreleased batches fall inside the investigation.
- Quarantine all product made on the line after the failure until it is resolved.
- Limit an operator’s activities until retraining and requalification, where the root cause points to operator activity.
- Resume production only after successful revalidation.
Identify isolates to species level where practical (Annex 1, 9.43). FDA asks the investigation to survey possible causes and assess the commercial product made since the last media fill. If no well-supported cause emerges, FDA says you may need three consecutive successful runs with closer scrutiny. The site normally runs corrective measures through its CAPA system, with an effectiveness check.
What Are the Common Misconceptions About Media Fill Results?
“A Passing Repeat Closes the Failure”
No. A passing repeat doesn’t close a failure. The investigation, corrective measures, the repeat series and the record review since the last successful APS all stay open until complete.
“FDA Bands Mean One Positive Is Acceptable”
Treat the bands as recommended responses. FDA calls any contaminated unit objectionable, and the manufacturer remains liable for nonsterile units.
“An End-of-Campaign APS Can Replace the Routine One”
An end-of-campaign APS is allowed only as extra assurance or for investigation. It must not replace the routine APS (Annex 1, 9.36 xiii).
“One Threshold Fits Every APS”
Unit counts, incubation and design vary by process, so the approved protocol and the applicable regulation set the rule.
Frequently Asked Questions
Under EU GMP Annex 1 (2022), none. The target is zero growth, and any contaminated unit fails the APS. FDA’s 2004 guidance gives bands by units filled, shown in the table above. Your protocol states the rule for your market.
Annex 1 says: “The target should be zero growth.” It then says any contaminated unit should result in a failed APS (paragraph 9.46). So a single positive unit is a failure that triggers the full response.
No. Annex 1 requires an investigation, corrective measures, normally at least three consecutive successful repeats and a review of records since the last successful APS. Product made after the failure stays quarantined until resolution.
They are FDA 2004 recommendations for US supply. Annex 1 uses no bands. Its 5,000 to 10,000 figure in paragraph 9.40 is a typical minimum of units filled, not a contamination limit.
All product made on the line after the failure is quarantined until the failure is resolved (Annex 1, 9.46). Records of aseptic production since the last successful APS get a prompt review and risk assessment, and other unreleased batches fall inside the investigation.
Summary
Annex 1 (2022) sets zero growth as the target, and any contaminated unit fails the APS. FDA’s 2004 guidance uses run-size bands. Count and reconcile every unit, investigate every failure fully, and follow the approved protocol. A single passing repeat never closes a failure.
References
- EU GMP Annex 1: Manufacture of Sterile Medicinal Products (2022), European Commission
- EudraLex Volume 4, European Commission
- Entry into force of revised Annex 1, PIC/S GMP Guide PE 009-17, PIC/S
- WHO TRS 1044 Annex 2: GMP for sterile pharmaceutical products, WHO
- Guidance for Industry: Sterile Drug Products Produced by Aseptic Processing, CGMP (September 2004), US FDA
Pankaj Sharma — Quality Control Specialist
Pankaj Sharma is a pharmaceutical QC professional who reviews our technical content for GMP accuracy, laboratory practices, and regulatory relevance.