GIFSQ Tools · Module 4 — Microbiology Methods & Laboratory Operations · Tool 79 of 500
Register a culture-collection strain: passage number against the maximum, viability, and storage temperature, with a review flag when it needs attention.
Try sample values — fills the form with the worked example below.
Culture register
Saved on this device only. Calculate a result first, then add it to the log.
| Date / time | Passage | Max | Viability (%) | Temp (°C) | Remaining | Status |
|---|
–
Passages remaining
–
Viability OK (≥ 70 %)
–
Status
Equation: Passages remaining = maximum passages − current passage number. Viability is acceptable at 70 % or above. Status is Review when no passages remain or viability is below 70 %.
Method: Culture-collection practice under ISO 11133 and recognised culture-collection guidance: limit subculturing (commonly to five passages from the master stock) to avoid drift, check viability on revival, and store working stocks frozen, typically at −80 °C or in liquid nitrogen.
Assumptions: the passage number counts subcultures from the master stock; viability is the measured recovery on revival.
Limitations: passage count and viability do not prove identity or purity — confirm the strain by its expected characteristics before use. The five-passage limit and the 70 % viability threshold are common laboratory practice, not values fixed by a standard.
Rounding: viability to 1 decimal place. Passage numbers are whole numbers.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Culture-collection practice under ISO 11133 and recognised culture-collection guidance: limit subculturing (commonly to five passages from the master stock) to avoid drift, check viability on revival, and store working stocks frozen, typically at −80 °C or in liquid nitrogen.
Assumptions: the passage number counts subcultures from the master stock; viability is the measured recovery on revival.
Limitations: passage count and viability do not prove identity or purity — confirm the strain by its expected characteristics before use. The five-passage limit and the 70 % viability threshold are common laboratory practice, not values fixed by a standard.
Rounding: viability to 1 decimal place. Passage numbers are whole numbers.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Passage 3 of a maximum of 5, viability 85 %, stored at −80 °C. Passages remaining = 2, viability is acceptable, so the status is OK.
Enter values above to see results.
Never subculture past the maximum — go back to the master stock instead. A strain at its passage limit or below 70 % viability needs review before it is used again. Tool 79 of 500 — GIFSQ
