This is a ready-to-use bench log for the single act this article calls out as the hardest one to get right in microbiology: recording an observation at the moment it happens, on a test where results take days to develop. Use it for any incubated plate, filter, or tube, whether it feeds environmental monitoring, bioburden, sterility, or an identification workflow. Replace every <<FILL: ...>> placeholder, keep one row per plate or per defined batch of plates read together, and maintain the log under document control. Field definitions, the blank log, instructions, retention, and a filled specimen follow. This is general guidance to adapt, not legal or regulatory advice.
Field definitions
| Field | Format | Required | Who enters | Definition |
|---|---|---|---|---|
| Sample / plate ID | Text | Yes | Analyst | The unique identifier linking this row to the sample and test record. |
| Test type | Text | Yes | Analyst | EM (viable/non-viable), bioburden, sterility, water, other. |
| Incubation start (date, time) | Date/time | Yes | Analyst | Recorded at the moment the plate or tube goes into incubation, not batched at end of shift. |
| Incubator ID | Text | Yes | Analyst | Which qualified incubator holds this plate. |
| Reading window (earliest, latest) | Date/time range | Yes | Analyst (from method) | The method-defined earliest and latest acceptable read time. |
| Read date and time (actual) | Date/time | Yes | Analyst | Recorded at the moment the plate is read, not after the fact. |
| Count / result | Number or descriptor | Yes | Analyst | The count (CFU) or observation (turbid/clear, growth/no growth). |
| Second-person verification (name, time) | Name, date/time | Where required | Verifier | Independent confirmation against the physical plate, before discard. |
| Isolate ID (if applicable) | Text | Where applicable | Analyst | Unique identifier if a colony is recovered for identification. |
| Analyst initials | Initials | Yes | Analyst | Who made the observation. |
Blank log
| Sample / plate ID | Test type | Incubation start | Incubator ID | Reading window | Read date/time (actual) | Count / result | 2nd-person verification | Isolate ID | Analyst |
|---|---|---|---|---|---|---|---|---|---|
<<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL: or N/A>> | <<FILL>> |
<<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> | <<FILL>> |
Instructions
- Complete the incubation start fields at the moment the plate or tube physically enters incubation, not at the end of the shift for a batch of plates.
- Complete the read fields at the moment the observation is made, at the reading station, not after returning to a desk.
- If a test runs multiple interim reads before a final result (for example a 14-day sterility observation), use one row per scheduled observation day rather than a single row completed only at the end.
- Second-person verification, where the parent SOP requires it, must be completed against the physical plate or a retained image before the plate is discarded; a verification dated after disposal is not acceptable and should be raised as a deviation, not recorded as routine.
- Assign an isolate ID at the moment any colony is recovered for identification, and carry it onto the identification record.
Retention
Retain this log under document control for not less than <<FILL: retention period, at least the retention of the results it supports>>. It is the primary evidence that a result destroyed or overgrown long ago was observed at the time and under the conditions the final report claims.
Filled specimen
| Sample / plate ID | Test type | Incubation start | Incubator ID | Reading window | Read date/time (actual) | Count / result | 2nd-person verification | Isolate ID | Analyst |
|---|---|---|---|---|---|---|---|---|---|
| BB-2026-0812-04 | Bioburden | 2026-08-12 08:10 | INC-03 | Day 3 to Day 5 | 2026-08-15 09:05 | 62 CFU | K. Osei, 09:11 | N/A | M. Delacroix |
| EM-2026-0812-A02 | EM, viable, Grade B | 2026-08-12 07:55 | INC-01 | Day 3 to Day 5 | 2026-08-14 10:20 | 1 CFU | K. Osei, 10:24 | ISO-2026-0611 | R. Nazarov |
| ST-2026-0810-11, Day 3 | Sterility | 2026-08-10 14:00 | INC-05 | Daily observation | 2026-08-13 08:30 | Clear, no turbidity | N/A (daily observation, not a countable result) | N/A | S. Rahman |
| ST-2026-0810-11, Day 14 | Sterility | 2026-08-10 14:00 | INC-05 | Daily observation | 2026-08-24 08:15 | Clear, no turbidity, final observation | T. Alvarez, 08:20 | N/A | S. Rahman |
The two sterility rows show how a single multi-day test still gets a contemporaneous row for each scheduled observation, rather than one row completed only at day 14 that cannot prove the intervening days were actually checked. The EM row shows the isolate ID captured at recovery, ready to carry onto the identification chain of custody.
Common inspection findings this log prevents
- A multi-day test (sterility, some bioburden methods) with only a final read recorded, no evidence the intervening scheduled observations happened.
- Read times recorded as a single batch time for plates actually read over an extended session.
- Second-person verification dated after the plate was already discarded.
- A recovered isolate with no assigned ID, so it cannot later be traced back to this log’s row.
How to adapt this log
- Align the reading window column to your own method-specific windows; they differ by test type and matrix.
- If your site uses an electronic LIMS for some of these tests, replicate the same field set there rather than only on paper, and confirm the LIMS timestamps are system-generated, not manually entered.
- Add columns for any additional test types your lab runs (for example water system plates or in-process monitoring) using the same contemporaneous-first structure.
- Confirm your retention period against your records retention schedule and the longest-lived result this log supports.