Regular assessment is essential to detect contamination early and take corrective actions.
1) Microbial Limit Tests
Purpose:
Determine the number and types of microorganisms present in non-sterile products.
Methods:
A) Total Viable Count (TVC)
Aerobic Plate Count: Determines the total number of aerobic bacteria.
Yeast and Mold Count: Uses selective media to count fungi.
B) Specified Microorganisms Testing
Indicator Organisms: Testing for E. coli, S. aureus, P. aeruginosa, and C. albicans.
Method: Enrichment and selective plating to detect presence.
Standards:
Set by pharmacopeias (USP, BP, EP) with acceptable limits.
2) Preservative Efficacy Testing (PET)
Purpose:
Evaluate the effectiveness of antimicrobial preservatives in the product.
Procedure:
Inoculation: Introduce a known quantity of test microorganisms into the product.
Incubation: Store samples under specified conditions.
Sampling: At intervals (e.g., 7, 14, 28 days), measure microbial counts.
Acceptance Criteria:
Reduction in microbial counts as per pharmacopeial standards.
3) Visual Inspection (Assessment of Microbial Contamination and Spoilage)
Observation:
Physical Signs: Discoloration, turbidity, gas formation, mold growth.
Containers: Swelling, leakage, or corrosion indicating microbial activity.
Limitations:
May not detect microbial contamination in early stages.
4) Chemical Tests
Detection of Metabolic By-products:
pH Changes: Microbial metabolism can alter pH.
Gas Production: Measurement of gas in sealed containers.
Analytical Methods:
High-Performance Liquid Chromatography (HPLC): Detect degradation products.
Spectrophotometry: Measure changes in absorbance due to microbial metabolites.
5) Rapid Microbiological Methods (RMM)
Purpose:
Provide faster results compared to traditional culture methods.
Techniques:
ATP Bioluminescence: Detects microbial ATP as an indicator of viability.
Flow Cytometry: Counts and analyzes microbial cells using fluorescent dyes.
PCR (Polymerase Chain Reaction): Detects microbial DNA or RNA.
Advantages:
Faster turnaround times; increased sensitivity.
6) Environmental Monitoring
A) Air Sampling:
Settle Plates: Expose agar plates to the environment to collect airborne microbes.
Active Air Samplers: Draw air through a filter or onto a culture medium.
B) Surface Sampling:
Swabs: Wipe surfaces and culture swabs.
Contact Plates: Press agar surfaces onto equipment or facility surfaces.
C) Personnel Monitoring:
Finger Dabs: Test gloves or hands of operators.
Gowning Evaluation: Check for contamination on protective clothing.
7) Endotoxin Testing
Purpose:
Detect endotoxins (lipopolysaccharides) from Gram-negative bacteria.
Method:
Limulus Amebocyte Lysate (LAL) Test: Uses blood cells from horseshoe crabs to detect endotoxins.
Application:
Important for injectables and ophthalmic products.
These are all the Assessment of Microbial Contamination and Spoilage