Microbial Limits Testing¶
Microbiological Quality Control for Peptide Products¶
Purpose¶
Microbiological testing ensures peptide products are free from microbial contamination and meet pharmacopeial standards for safety.
Test Methods¶
| Test | Method | Standard | Limit |
|---|---|---|---|
| TAMC (Total Aerobic Microbial Count) | Plate count | USP <61> | ≤100 CFU/g |
| TYMC (Total Yeast/Mold Count) | Plate count | USP <62> | ≤20 CFU/g |
| Endotoxin (Bacterial) | LAL / rFC | USP <85> | ≤5 EU/mg |
| Staphylococcus aureus | Enrichment | USP <62> | Absent in 1 g |
| Pseudomonas aeruginosa | Enrichment | USP <62> | Absent in 1 g |
| Sterility | Membrane filtration | USP <71> | Sterile |
Endotoxin Testing¶
Recombinant Factor C (rFC) Method¶
- Synthetic alternative to Limulus amebocyte lysate
- No animal-derived components
- Equivalent sensitivity to LAL
| Endotoxin Source | Test Sensitivity |
|---|---|
| E. coli | 0.005 EU/mL |
| P. aeruginosa | 0.005 EU/mL |
| S. enterica | 0.005 EU/mL |
Interference Testing¶
Before routine testing, confirm no matrix interference:
- Spike sample with known endotoxin (0.5 EU/mL)
- Test spiked and unspiked sample
- Recovery 50–200% = no interference
Bioburden Sampling Plan¶
| Batch Size | Samples | Sampling Points |
|---|---|---|
| <100 units | 5 | Start, middle, end |
| 100–500 units | 10 | Systematic |
| >500 units | 20 | Multiple points |
🔗 Related: Endotoxin Testing | Quality Control Overview | Peptide Quality Control Guide