of suitable microorganisms, as per pharmacopeial guidelines.

2. Scope

This procedure applies to the Analytical Method Development (AMD) and Microbiology departments for all batches of culture media prepared or procured for microbial limit testing, environmental monitoring, sterility testing, and pathogen detection.

3. Responsibilities

• Microbiologist: Conducts GPT on media lots and records data accurately.
• Media Preparer: Prepares the media aseptically and ensures traceability of components.
• QA Officer: Reviews and verifies GPT protocol adherence and documentation.
• Head – AMD: Approves final protocol and validates acceptance of GPT results.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring proper implementation and documentation of Growth Promotion Test protocols.

5. Procedure

5.1 Media Types and Storage Conditions

1. Common media to be tested:
   • Tryptic Soy Agar (TSA)
   • Fluid Thioglycollate Medium (FTM)
   • Soybean Casein Digest Medium (SCDM)
   • Sabouraud Dextrose Agar (SDA)
   • MacConkey, Mannitol Salt, Cetrimide, XLD Agar
2. Store media at 2–8°C (solid) or room temperature (broths) unless otherwise specified.
3. Assign lot numbers and record preparation details in Annexure-1: Media Preparation and Storage Log.

5.2 Selection and Revival of Microorganisms

1. Use certified reference strains (e.g., ATCC/MTCC):
   • Staphylococcus aureus (ATCC 6538)
   • Escherichia coli (ATCC 8739)
   • Pseudomonas aeruginosa (ATCC 9027)
   • Bacillus subtilis (ATCC 6633)
   • Candida albicans (ATCC 10231)
2. Revive cultures on non-selective media and incubate at 30–35°C or 20–25°C depending on organism type.
3. Prepare inoculum of ≤ 100 CFU/mL by serial dilution in sterile saline or peptone water.
4. Document strain handling in Annexure-2: Microbial Culture Revival Log.

5.3 Growth Promotion Test Procedure

1. Label and assign each media lot for GPT testing with organism identification.
2. Inoculate duplicate plates/tubes of each media with 0.1 mL of appropriate diluted inoculum.
3. Use uninoculated media as negative controls.
4. Incubate under conditions suitable for organism recovery:
   • TSA: 30–35°C for 3 days
   • SDA: 20–25°C for 5 days
   • FTM/SCDM: 30–35°C for 14 days
5. Record growth as ‘acceptable’ if colony morphology and count match expected ranges (typically 50–200% recovery compared to control media).
6. Log in Annexure-3: GPT Execution Sheet.

5.4 Acceptance Criteria

1. Growth must be evident and comparable to a control media batch tested concurrently.
2. No growth should occur in negative control plates.
3. Any deviations must be documented and investigated before release of the media batch.

5.5 Documentation and Reporting

1. Summarize all inoculation conditions, microbial strains, recovery counts, and growth observations.
2. Attach control data and photographic documentation where applicable.
3. Prepare final GPT report and submit for QA and department head approval.
4. Archive in Annexure-4: GPT Summary Report.

6. Abbreviations

• GPT: Growth Promotion Test
• TSA: Tryptic Soy Agar
• FTM: Fluid Thioglycollate Medium
• CFU: Colony Forming Unit
• SOP: Standard Operating Procedure

7. Documents

1. Media Preparation and Storage Log – Annexure-1
2. Microbial Culture Revival Log – Annexure-2
3. GPT Execution Sheet – Annexure-3
4. GPT Summary Report – Annexure-4

8. References

• USP <61> and <62> – Microbial Limit Tests
• USP <71> – Sterility Tests
• EP 2.6.1 / 2.6.12 / 2.6.13 – Microbiological Methods

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Media Preparation and Storage Log

Media	Batch No.	Preparation Date	Storage Temp	Expiry
TSA	TSA0525	18/05/2025	2–8°C	18/06/2025

Annexure-2: Microbial Culture Revival Log

Organism	Source	Revival Date	Used For
B. subtilis	ATCC 6633	17/05/2025	TSA GPT

Annexure-3: GPT Execution Sheet

Media	Organism	CFU Inoculated	Recovery	Result
TSA	E. coli	80	76	Pass

Annexure-4: GPT Summary Report

Growth Promotion Test confirmed that all tested media lots supported expected microbial recovery within limits. Negative controls showed no contamination. Media batches TSA0525 and SDA0525 are approved for microbiological use.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Expanded to include automated ID systems and multiple incubation guidelines	Annual Update