Sterilization Indicator Tape's working principle

Sterilization Indicator Tape is a chemical indicator widely used for external process validation in sterilization processes such as autoclaving, ethylene oxide (EO), or hydrogen peroxide plasma. It does not prove sterility, but provides a direct and rapid indication of whether items have been exposed to the intended sterilization conditions (such as temperature, time, and steam saturation).

Mechanism of Action: Based on a thermosensitive/chemical color-changing reaction.

The core mechanism is a controlled thermo-induced chemical reaction. Thermosensitive ink color change (mainstream, suitable for steam sterilization). The tape surface is printed with a specially formulated thermosensitive dye + developer + adhesive system (often a mixture of organic acid salts/metal complexes).

When continuously exposed to a saturated steam environment at **≥121°C** for several minutes (typically 3–15 min), the heat triggers an irreversible chemical reaction, leading to a change in molecular structure → a significant and permanent color change.

Common color-changing patterns: Off-white/light yellow base → Dark brown, black, or dark green stripes

Light gray stripes → Dark blue/purple-black

Key point: Color change ≠ successful sterilization; it only indicates that "the set temperature threshold was reached and maintained for a sufficient time." If the packaging is too tight and steam cannot penetrate, the interior may still not be sterilized.