Sterilization methods
Seven ways to sterilize a medical device. This catalog currently has verified product data for one of them — steam. The rest are covered here for reference, not as a shopping list.
The seven methods
A short, factual overview of how each method removes microbial life — not a buying guide for methods we don't stock.
Steam (Moist Heat)
Saturated steam under pressure, typically 121–134°C. The dominant method for reusable surgical and dental instruments — fast cycles, no toxic residue, but not compatible with heat-sensitive materials.
- Typical cycle: 134°C for 3–4 minutes (flash) or 121°C for 15–20 minutes
- Requires a validated Bowie-Dick test each operating day for porous loads
- Chemical and biological indicators confirm real lethality, not just temperature reached
- Not compatible with most plastics, powders, or anhydrous oils
Ethylene Oxide (EO)
A gas that sterilizes at low temperature, used for heat- and moisture-sensitive devices like electronics and some plastics. Requires long aeration times to clear toxic residue.
- Operating range typically 37–63°C, far below steam sterilization temperatures
- Aeration can take 8–12 hours to clear residual toxic gas from the load
- Classified as a human carcinogen — requires dedicated ventilation and exposure monitoring
- Common choice for single-use catheters, implants, and electronic assemblies
Gamma Irradiation
Ionizing radiation from a cobalt-60 source, used for industrial-scale single-use device sterilization. Penetrates sealed final packaging, so it's done after the product is boxed.
- Dose typically validated at 25–40 kGy depending on product bioburden
- Performed at contract irradiation facilities, not on-site at the manufacturer
- Can degrade some polymers or discolor certain plastics over time
- No temperature or moisture exposure involved, unlike steam or EO
Electron Beam (E-beam)
High-energy electrons instead of gamma photons. Faster dose delivery and no radioactive source, but shallower penetration — better suited to lower-density loads.
- Delivers dose in seconds rather than the hours gamma irradiation requires
- Lower penetration than gamma — best suited to low-density, thin-profile loads
- No radioactive source to store, shield, or dispose of at end of life
- Increasingly used for single-use packaging and low-density device trays
Vaporized Hydrogen Peroxide (VHP)
A low-temperature gas plasma or vapor method for heat-sensitive instruments and enclosed spaces, including some isolators and endoscopes.
- Typical cycle temperature stays under 50°C throughout
- Leaves only water vapor and oxygen as breakdown byproducts
- Common choice for endoscopes, cameras, and other moisture-sensitive optics
- Cycle times generally shorter than EO but longer than standard steam
Dry Heat
Hot air at 160–190°C for extended cycles. Used for materials that steam would corrode or that oil/powder would trap moisture around, like some metal instruments and glassware.
- Requires longer exposure than steam: often 1–2 hours at 160°C
- No moisture involved, so no corrosion risk for anhydrous oils or powders
- Poor packaging penetration — mainly used for unwrapped or open loads
- Common choice for glassware, oils, and powders that steam would degrade
Low-Temperature Steam and Formaldehyde (LTSF)
Steam below 100°C combined with formaldehyde gas, mainly used in parts of Europe for thermolabile instruments where EO isn't preferred.
- Operates below 100°C, gentler on thermolabile instruments than standard steam
- Formaldehyde residue and off-gassing require dedicated aeration handling
- Used mainly in parts of Europe; largely phased out elsewhere
- Requires its own penetration test, distinct from the standard Bowie-Dick test
What's actually live in the catalog
Steam is the only method with verified products behind it right now. The other six are listed above for reference — we don't show a method as “available” until there's real product data to back it.
Steam sterilization — dental tabletop autoclaves
5 verified dental tabletop autoclave models, an interactive selector by chamber volume, and 2 in-depth guides on reading the results.
- Biological indicators: the only test that measures an actual kill
- The drying phase: why a Class B cycle isn't finished when the pressure gauge hits zero
- Immediate-use steam sterilization (IUSS): what actually changes about the process
- A biological indicator comes back positive: what actually has to happen next
- Process challenge devices: monitoring a real load, not an empty chamber
- Vacuum leak test vs. Bowie-Dick test: two different daily checks, easily mixed up
- Autoclave tape turned black — does that mean the load is sterile?
- Chemical indicator classes 1–6: which one belongs on which pack
- EN 13060 Class N, S, and B: what the autoclave classes actually mean
- Reading a Bowie-Dick test: a step-by-step guide
Need to size an autoclave for your practice or clinic?
Open the sterilizer selector