The end of the day is when it happens at most clinics: the last load comes out of the autoclave, and someone remembers the biological indicator still has to go in. It is the easiest task of the day to skip, and one of the most important. Spore testing dental clinics with a biological indicator (BI) is the only way to prove a sterilizer actually killed resistant microorganisms — not just reached a number on a gauge. Ontario's dental regulator expects it on every day the sterilizer is used, and does not treat it as optional.
Why Ontario dental standards require daily biological monitoring
Chemical indicators — the stripes that change colour on pouches and tape — show that the right conditions were present: heat, steam, time. They do not show that anything was actually killed. A biological indicator holds live bacterial spores, typically Geobacillus stearothermophilus, which are far harder to destroy than anything found on dental instruments. If the cycle kills those spores, it killed your load. That is why ISO 11138 governs how these indicators are manufactured, and why CSA Z314.8 — the Canadian standard for effective sterilization in health care settings — treats biological monitoring as the core of a sterilization program.
Health Canada and provincial dental colleges take the same position: a dental autoclave monitoring program without regular spore testing is incomplete. In practical terms, that means running a biological indicator for every sterilizer in the office on each day it is used, and for each type of cycle used that day. If you run two autoclaves, each one gets its own test, its own control, and its own log entry.
The daily spore test, step by step
Once you have done it a few times, the whole routine takes about ten minutes of hands-on time plus a 24-hour incubation. This sequence works in most Canadian clinics:
- Place the BI in the hardest-to-sterilize location — usually the front of the chamber on the lower tray, inside a sealed pouch or wrapped cassette, exactly where steam has the toughest time reaching.
- Run a normal cycle with a routine load. Do not run an empty or extended cycle; you want to test what actually happens during real use.
- After the cycle, remove the BI, activate it according to the instructions, and place it in the incubator next to the positive control that came in the pack.
- Read the result at 24 hours. A colour change in the growth medium means spores survived — that is a failed test.
- Record the outcome in your sterilization log with the date, cycle number, operator, and load contents, even when the result is a pass.
What a compliant daily monitoring plan looks like
The Ontario requirement is wider than "test once a day". The frequency is one biological indicator for each sterilizer on each day it is used, and once for each type of cycle used that day, with a control processed alongside it. Set out as a table, the gaps become visible.
| What you monitor | Frequency | Cycle types | What goes in the record |
|---|---|---|---|
| Routine sterilizer use | Each day the sterilizer is used | Each type of cycle used that day | Date, sterilizer and load or cycle number, indicator lot, result, and the person who ran the test |
| Control indicator | With every monitoring run | Same cycle type as the test indicator | Control result and the incubation start time |
| Implantable loads | Every load containing implantable devices | That cycle | Indicator result before release; implants stay quarantined until the result is known |
| A positive result | Immediately, until it is resolved | Repeat in the same cycle type | Investigation, corrective action and the re-test result |
| The log itself | Continuous | All cycles | Kept at least 10 years from the last entry in Ontario |
Sources checked 2026-10-01: the college's infection prevention and control standard (biological monitoring section) and the provincial guidance for cleaning, disinfection and sterilization in health care settings, which states the same each-day, each-cycle-type rule for biological monitoring.
When a spore test comes back positive
A positive result is not the end of the world, but it is a stop-everything moment. Everything from that cycle is considered non-sterile until proven otherwise. This is the sequence we walk clinics through:
- Isolate everything from the failed cycle. Do not return it to circulation, and do not reprocess it in the same machine until you understand what happened.
- Retest the sterilizer right away, ideally with a fresh biological indicator from a different lot.
- Look for root causes: overloading, poor steam quality, a worn door gasket, pouches sealed incorrectly, or a chamber that has not been cleaned in months.
- Notify the team and your sterilizer service provider, and document every step. The CDC Guidelines for Infection Control in Dental Health-Care Settings expect a written record of the investigation, and so do most provincial colleges.
Record keeping that stands up to an audit
CDC guidance is blunt on this point: if it was not documented, it did not happen. For dental autoclave monitoring, that means a log entry for every cycle, including the daily biological indicator. Record the BI result, the lot number of the indicator, the incubator reading, and the name of the person who ran the test. Canadian dental colleges typically ask practices to keep sterilization records for a defined period — check your provincial requirement and hold on to the logs longer than you think you need to.
What an Ontario audit actually asks for
The college's infection prevention and control self-audit form counts twenty record fields across four groups: nine in the load log, five on the package label, three in the service and maintenance log, and three in the malfunction record. Documenting all four is what turns a daily routine into evidence.
| Record group | Fields the audit looks for | Where it lives |
|---|---|---|
| Load log | Date; sterilizer number; load number; load contents; cycle; sterilization time; temperature; pressure; name of the person responsible | Reprocessing logbook kept beside the sterilizer |
| Package label | Date; sterilizer used; load or cycle number; contents when not visible; initials of the person responsible | On each pack, next to the indicator |
| Service and maintenance log | Three fields covering the sterilizer's servicing | Maintenance file |
| Malfunction record | Three fields covering each malfunction episode | Incident file |
| Two rules outside the field count | The logbook carries physical, chemical and biological results together, and is retained for ten years after the last entry | Same logbook |
Two details sit outside the numbered fields but decide how an audit feels: the incubator reading for each test, and the date the result was read. Recording both takes a few seconds and shortens any later review. Clinics that reach daily monitoring across two or more sterilizers usually step up to a bulk self-contained indicator pack rather than re-ordering small boxes every fortnight.
Why autoclaves fail spore tests (and how to avoid it)
- Overloading. When pouches are packed too tightly, steam cannot sweep past every surface, and trapped air protects the spores.
- Steam quality. Wet steam, low pressure, or a chamber that does not purge air fully will fail a BI even on a light load.
- Sealing and packaging. Pouches taped shut, torn paper, or instruments crammed past the seal line defeat the entire cycle.
- Skipped maintenance. A sterilizer that is never cleaned or serviced will eventually fail, and the spore test is usually the first sign.
None of this requires exotic equipment. A 24-hour self-contained biological indicator, a small incubator, and a logbook are the whole kit. CliniEco's biological indicator pack gives you ten tests with controls — about two weeks of daily testing for one autoclave — and the 24-hour readout means you know the result before Monday's patients arrive. Pair it with CliniEco's class 4 sterilization pouches (ISO 11140-1 class 4 chemical indicators) and autoclave tape so your packaging is never the reason a good cycle fails. Compared to Medicom's or 3M's equivalent kits, the routine is identical — same incubation window, same controls — and switching brands does not change your protocol.
How Often to Do Spore Test in Dental Office RCDSO
Every day the sterilizer is used. In Ontario, the RCDSO infection prevention and control standard requires a biological indicator in a process challenge device on each day the sterilizer is operated, and for each type of cycle used. Weekly testing is the United States CDC / AAMI ST79 baseline, not the Ontario requirement. Plan roughly 250 indicators per sterilizer per year on a five-day week.
Related reading: browse the dental compliance hub for more clinic-ready sterilization guides.
Related: Never re-order sterilization supplies again — monthly plan from $69/month.
read our dental sterilization monitoring compliance pillar for RCDSO rules.
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Frequently Asked Questions
How Often to Do Spore Test in Dental Office RCDSO
In Ontario, follow the RCDSO: run a biological indicator for each sterilizer on every day the sterilizer is used, not once a week. A clinic that runs five days a week therefore needs roughly five indicators per sterilizer per week, about 250 a year. Test every cycle type you run, not only the standard load, and record each result the day it is read. The weekly baseline belongs to the CDC and AAMI ST79 in the United States; it does not satisfy the Ontario college requirement.
What counts as a spore test for RCDSO purposes?
Only a biological indicator counts. A self-contained vial of Geobacillus stearothermophilus spores, manufactured to ISO 11138-3, is processed inside a process challenge device in a normally loaded cycle, then incubated and read. Autoclave tape, external chemical indicators, and Class 5 or Class 6 strips show that cycle conditions were met, but they cannot prove the spores died. Keep the incubator log beside the sterilizer so a positive result is caught the day it appears.
Last updated: September 2026
Related reading
- Rapid Readout Biological Indicator Readers: Every Major Brand Compared (2026 Canada Price Guide)
- BI vs Chemical Indicators: What's the Difference in Sterilization Monitoring?
- The Real Annual Cost of Biological Monitoring: Locked Ecosystems vs Open-System BIs in Canadian Dental Clinics
- dental clinic sterilization supplies
- free Ontario sterilization compliance log
- printable autoclave sterilization log sheet (free)
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