products as per regulatory requirements in USP <62>, IP, and EP.

2. Scope

This procedure applies to the Analytical Method Development (AMD) department and microbiology laboratories for the development of test methods intended to detect pathogens such as Escherichia coli, Salmonella spp., Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans in pharmaceutical raw materials and finished products.

3. Responsibilities

• Microbiologist: Prepares cultures, executes test procedures, and analyzes results.
• Analytical Scientist: Assists with product sample preparation and enrichment strategy.
• QA Officer: Verifies that test development and validation comply with regulatory guidelines.
• Head – AMD: Reviews and approves the method development protocol and final validation report.

4. Accountability

The Head of Analytical Method Development is accountable for ensuring the scientific integrity and regulatory compliance of all pathogen detection methods developed.

5. Procedure

5.1 Pathogen Panel and Culture Procurement

1. Obtain standard cultures (e.g., ATCC or MTCC) of:
   • Escherichia coli (ATCC 8739)
   • Salmonella typhimurium (ATCC 14028)
   • Staphylococcus aureus (ATCC 6538)
   • Pseudomonas aeruginosa (ATCC 9027)
   • Candida albicans (ATCC 10231)
2. Revive cultures using nutrient broth or SCDM and incubate at 30–35°C for 18–24 hours.
3. Prepare working suspensions with 10–100 CFU/mL and confirm counts by spread plating.

5.2 Sample Preparation and Enrichment

1. Prepare the required quantity of the product sample as per pharmacopoeial guidelines.
2. For each pathogen, inoculate test sample and control media separately with the respective organism.
3. Enrich the product in:
   • Buffered Sodium Chloride Peptone Solution (pH 7.0) or Casein Soya Bean Digest Broth (SCDM)
   • Incubate at 30–35°C for 18–24 hours
4. Document in Annexure-1: Enrichment and Inoculation Log.

5.3 Selective Media and Isolation

1. After enrichment, subculture onto selective media:
   • E. coli: MacConkey Agar (lactose fermenting colonies)
   • Salmonella: XLD Agar (red colonies with black centers)
   • S. aureus: Mannitol Salt Agar (yellow colonies)
   • P. aeruginosa: Cetrimide Agar (green pigment)
   • C. albicans: SDA with chloramphenicol
2. Incubate media plates as per organism requirements (usually 30–35°C for 18–72 hours).
3. Record observations in Annexure-2: Pathogen Isolation Record.

5.4 Confirmatory Identification

1. Perform confirmatory tests:
   • Gram staining
   • Biochemical tests (e.g., TSI, catalase, oxidase, urease)
   • API strips or automated ID systems (optional)
2. Compare results with ATCC strain characteristics.
3. Document in Annexure-3: Confirmatory ID Sheet.

5.5 Method Validation and Recovery Study

1. Spike product samples with known CFU levels of each pathogen.
2. Conduct enrichment, selective plating, and identification as per the developed method.
3. Recovery must be demonstrated from product equivalent to control (within ±50% variation).
4. Document results in Annexure-4: Method Validation Report.

6. Abbreviations

• CFU: Colony Forming Unit
• USP: United States Pharmacopeia
• ATCC: American Type Culture Collection
• SCDM: Soybean Casein Digest Medium
• SOP: Standard Operating Procedure

7. Documents

1. Enrichment and Inoculation Log – Annexure-1
2. Pathogen Isolation Record – Annexure-2
3. Confirmatory ID Sheet – Annexure-3
4. Method Validation Report – Annexure-4

8. References

• USP <62> – Tests for Specified Microorganisms
• IP / EP Pathogen Detection Guidelines
• ICH Q6A – Specifications: Test Procedures

9. SOP Version

Version: 2.0

10. Approval Section

	Prepared By	Checked By	Approved By
Signature
Date
Name
Designation
Department

11. Annexures

Annexure-1: Enrichment and Inoculation Log

Sample	Organism	Media	Inoculum Level	Incubation
PD-124	S. aureus	SCDM	100 CFU	30°C / 24h

Annexure-2: Pathogen Isolation Record

Organism	Media	Colony Morphology	Result
S. aureus	MSA	Yellow colonies	Positive

Annexure-3: Confirmatory ID Sheet

Organism	Test	Observation	Result
S. aureus	Catalase	Bubbles formed	Positive

Annexure-4: Method Validation Report

Method successfully detected all five target pathogens at 100 CFU spike level. Recovery ≥ 50% compared to controls. Method is suitable for routine pathogen detection in oral and parenteral dosage forms.

Revision History:

Revision Date	Revision No.	Details	Reason	Approved By
04/05/2025	2.0	Expanded to include confirmatory ID steps and organism-specific media	Regulatory Update