The KRINKO/BfArM Recommendation 2012 and DIN EN 13060 define the requirements for routine sterilizer testing. Daily Bowie-Dick/Helix tests, regular biological controls with spore indicators, and batch-by-batch documentation are required. This guide details the different types of controls, their frequency, and documentation obligations under German law.
German sterilization standards, defined by the KRINKO/BfArM Recommendation of 2012 and aligned with DIN EN 13060, require a triple validation system for every autoclave. Physical indicators are the parameters displayed by the autoclave itself (temperature, pressure, duration) -- they confirm that the cycle ran according to the selected program. Chemical indicators (autoclave tape, chemical integrators) change color when exposed to sterilization conditions. Biological indicators (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 MPBetreibV (Medical Devices Operator Ordinance) Section 8 requires compliance with recognized standards of technology in reprocessing.
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 (KRINKO/BfArM 2012). DIN EN 13060 establishes this as a requirement for Class B and Class S autoclaves with pre-vacuum cycles.
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 Chargendokumentation (load documentation) 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.
Recommended frequency: weekly as general best practice, after every new installation or autoclave repair, and whenever there is any doubt about the equipment's performance. The DGSV Fortbildungsempfehlung (continuing education recommendation) emphasizes the importance of qualified personnel (MPBetreibV Section 5) for the correct execution and evaluation of biological controls. 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) 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 simultaneously.
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 with high instrument volume, the use of Class 5 or 6 integrators in every load is recommended practice per the DAHZ Hygieneleitfaden (Dental Hygiene Guidelines).
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 Chargendokumentation (load documentation) and must be retained for a minimum of 5 years (MPBetreibV). During Praxisbegehungen (practice inspections) by the Gesundheitsamt, all records must be available for immediate review.
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 for sterilized instruments, see the dedicated guide.
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