Biological and physico-chemical autoclave controls verify that every sterilization cycle reaches the required parameters. The NP EN ISO 17665-1:2010 and EN 13060 standards (adopted in Portugal by IPQ) define the control system: vacuum leak tests, daily Bowie-Dick and Helix tests for prevacuum autoclaves, chemical indicators on every pouch, and biological indicators with Geobacillus stearothermophilus spores at a frequency defined by risk analysis. The ERS dental-clinic inspection form (mod-133_02) explicitly verifies the automatic or mechanical recording of cycles. This guide describes the control types, the required frequency, and the documentation obligations.
Portuguese sterilization standards, aligned with NP EN ISO 17665-1:2010 and NP EN 13060, require a triple validation system for every autoclave. Physical indicators are the parameters displayed by the autoclave itself (temperature, pressure, holding time) — they confirm that the cycle ran according to the selected program. Chemical indicators (autoclave tape, chemical integrators per NP EN ISO 11140-1) change color when exposed to sterilization conditions. Biological indicators (NP EN ISO 11138 spore tests) are the most reliable: they confirm that the most resistant microorganisms have been destroyed.
Each level provides a different type of assurance. Physical indicators confirm the machine operated correctly. Chemical indicators confirm that sterilization conditions reached the instruments inside the pouches. Biological indicators confirm that sterilization was actually achieved at a microbiological level. All three levels are necessary — no single indicator is sufficient on its own. The ERS dental-clinic inspection form (mod-133_02) explicitly verifies the recording of these controls.
The Bowie-Dick test (for pre-vacuum autoclaves) or Helix test (for hollow loads) verifies steam penetration into the load. It must be performed daily, before the first load of the day, in an empty autoclave. NP EN 13060 sets it as a requirement for any Class B or Class S autoclave with a pre-vacuum cycle.
A failed Bowie-Dick test indicates a steam penetration problem — it could be a leak, a vacuum pump issue, or a worn gasket. The autoclave must not be used until the problem is resolved. The test result (pass or fail) must be recorded in the sterilization register along with the date and any corrective action taken.
The vacuum leak test verifies that the autoclave maintains the vacuum required during the pre-vacuum phase of the cycle. A leak compromises steam penetration — instruments at the center of the load may not be sterilized. This test is recommended weekly and mandatory after any maintenance on the vacuum system.
The door seal (gasket) should also be checked regularly. A worn or damaged seal causes steam leaks, failed cycles, and premature wear on the vacuum pump. SecuSteri allows you to record the results of all these checks (vacuum test, seal check, Bowie-Dick, Helix, biological indicators) directly in the digital register, linked to the day and the autoclave concerned.
Biological indicators contain spores of Geobacillus stearothermophilus, the microorganism most resistant to saturated steam. If the sterilization cycle destroys them, it will destroy any other microorganism. They are the definitive proof that sterilization was effective, under the NP EN ISO 11138 family.
Recommended frequency is set by risk analysis in the establishment's quality plan — weekly is the accepted professional standard, monthly is a prudent minimum. APPTBP recommends periodic biological controls for tattoo and piercing studios. After any failed biological test, the autoclave must be taken out of service until the cause is identified and resolved, and all instruments processed since the last successful test must be considered non-sterile.
Autoclave tape (Class 1 indicator, NP EN ISO 11140-1) is placed on each pouch. It does not guarantee sterilization — it merely indicates that the pouch has been through the autoclave. Chemical integrators (Class 4, 5, or 6) provide more thorough verification by measuring exposure to temperature, pressure, and time.
The Class 6 chemical integrator is the most reliable chemical indicator: it only changes color when all critical cycle parameters have been reached. For dental practices in Portugal, the use of at least one chemical integrator per load is recommended. For tattoo and piercing studios, autoclave tape on every pouch is the minimum professional standard recommended by APPTBP.
Every biological and physico-chemical control must be documented: date, type of test, result (pass/fail), and any corrective action taken. These records are an integral part of the sterilization register and must be available during ERS or IGAS inspections. The general healthcare-record convention applies — 5 years is a prudent minimum.
Digital traceability allows control results to be archived automatically and linked to the relevant sterilization cycles, eliminating the risk of loss or oversight. For more details on use-by dates, see the dedicated guide.
For a complete schedule of daily, weekly, monthly, quarterly, and yearly autoclave maintenance tasks, see our Autoclave maintenance guide.