This is a ready-to-use record for a biological indicator challenge. It captures what a BI challenge must prove and, just as important, that the challenge itself was valid (the spores were viable to begin with). Use one record per run. Replace every <<FILL: ...>> placeholder with your own specifics. A worked filled specimen and a field-definition table follow. Confirm each cited standard against the current source before you rely on it.
Record header
| Field | Format | Required | Entry |
|---|---|---|---|
| Record number | text | Yes | <<FILL: BI-REC-ID>> |
| Protocol / study reference | text | Yes | <<FILL: PQ protocol number, test case>> |
| Sterilizer / cycle | text | Yes | <<FILL: ID and cycle name>> |
| Run type | half-cycle / full-cycle | Yes | <<FILL>> |
| Date of run | date | Yes | <<FILL>> |
1. Biological indicator identity
| Field | Entry |
|---|---|
| Organism | <<FILL: Geobacillus stearothermophilus>> |
| BI form | <<FILL: spore strip / self-contained BI / inoculated product / PCD>> |
| Manufacturer and lot | <<FILL>> |
| Certified population N₀ per unit | <<FILL: e.g. 1.2 x 10^6 CFU>> |
| Certified D₁₂₁ | <<FILL: e.g. 1.8 min>> |
| Certificate expiry | <<FILL>> |
2. Exposure
| Field | Entry |
|---|---|
| Intended routine exposure | <<FILL: e.g. 121 degC, 30 min>> |
| Exposure applied this run | <<FILL: e.g. 15 min for a half cycle>> |
| Number of BIs placed | <<FILL>> |
| Placement (locations) | <<FILL: worst-case and representative, per placement diagram>> |
| Co-located thermocouples | <<FILL: probe IDs>> |
3. Incubation
| Field | Entry |
|---|---|
| Incubation temperature | <<FILL: e.g. 55-60 degC for G. stearothermophilus>> |
| Incubation period | <<FILL: validated readout, e.g. up to 7 days for strips, or reduced per manufacturer data>> |
| Recovery medium / method | <<FILL>> |
| Incubator ID | <<FILL>> |
4. Controls (both required every run)
| Control | Purpose | Expected | Result |
|---|---|---|---|
| Positive control (unexposed BI, same lot) | Proves the spores were viable | Growth | <<FILL: Growth / No growth>> |
| Negative control (sterile medium) | Proves no contamination | No growth (sterile) | <<FILL: Sterile / Growth>> |
A positive control that does not grow invalidates the run: a “kill” cannot be claimed if the spores were not shown to be alive.
5. Results
| BI ID | Location | Growth / No growth | Reader | Date read |
|---|---|---|---|---|
<<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> |
| Field | Entry |
|---|---|
| Number of BIs positive (growth) | <<FILL>> |
| Acceptance for this run type | <<FILL: half-cycle overkill = all BIs no growth; full cycle = all inactivated>> |
| Controls valid | <<FILL: Yes / No>> |
| Run result | <<FILL: Pass / Fail / Invalid>> |
6. Field definitions
| Field | Definition |
|---|---|
| N₀ | Certified spore population per BI unit before exposure. |
| D₁₂₁ | Time at 121 °C to reduce the population by one log (90 percent). |
| Half-cycle | A run at half the intended exposure time; complete kill of ≥ 10⁶ spores implies ≥ 12-log delivery by the full cycle. |
| Positive control | An unexposed BI from the same lot, incubated to confirm viability. |
| Negative control | Uninoculated medium, incubated to confirm the recovery method is not contaminated. |
| Invalid run | A run whose controls failed (positive control did not grow, or negative control grew); results cannot be used. |
7. Signoff and retention
| Role | Name | Signature | Date |
|---|---|---|---|
| Performed by | <<FILL>> | ||
| Reviewed by (microbiology) | <<FILL>> | ||
| QA | <<FILL>> |
Retention: not less than <<FILL: retention period>> per the records retention schedule. These are GMP records subject to ALCOA+.
8. References
USP <55> (BI resistance performance tests), <1035> (BIs for sterilization), <1229.5> (BIs for sterilization by direct contact). ISO 11138-1 and -3 (biological indicators, general and moist heat). ISO 17665 (moist heat validation); 21 CFR 211.113(b); EU GMP Annex 1 (2022).
Describe copyrighted standards in your own words; confirm current editions before use.
Filled specimen
A half-cycle run for an example overkill porous-load cycle.
| Field | Entry |
|---|---|
| Record number | BI-REC-2026-044 |
| Run type | Half-cycle (15 min at 121 °C) |
| BI | G. stearothermophilus, self-contained, lot 5521, N₀ = 1.2 × 10⁶, D₁₂₁ = 1.8 min |
| BIs placed | 20, at pack centers and drain per placement diagram |
| Incubation | 57 °C, read at 48 h (reduced readout per manufacturer data) |
Controls: positive control grew (spores viable); negative control sterile. Controls valid.
Results: 0 of 20 BIs showed growth. Acceptance for a half cycle (complete kill of ≥ 10⁶ spores) met. Run result: Pass.
Because the positive control grew, the no-growth of the 20 exposed BIs is a genuine kill, not a lot of dead spores. That single check is what separates a defensible half-cycle result from a finding.
Common inspection findings this record prevents
- A half cycle “passed” on a BI lot that was never shown to be viable (no positive control).
- BI D-value or population not recorded, so the lethality math cannot be reconstructed.
- Incubation temperature or period not matched to the organism and the validated readout.
- A negative control omitted, so a contamination event could be misread as growth.
How to adapt this form
- Match the incubation temperature and period to your organism and the manufacturer’s validated readout.
- Record the BI lot certificate values (N₀ and D₁₂₁) so the F0 and log-reduction math ties out.
- Treat a failed positive control as an automatic invalid run and investigate the lot and incubation.
- Keep the placement diagram with the record so the challenge locations are reproducible.