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Sterilisation and disinfection

Disinfection reduces the number of microorganisms on a surface to a level considered safe; sterilisation removes all of them, spores included. They are not two grades of the same thing but two distinct processes with different equipment, and each item needs one or the other depending on what it touches.

Where exactly is the line?

At spores. Many microorganisms are easy to kill with a good disinfectant left on for the contact time its data sheet specifies. Some bacteria, though, can take on a resistant form, the spore, which survives drying and a good share of the usual chemicals. A disinfectant brings the microbial load down to a level that is safe for a surface; only a sterilisation process also eliminates those resistant forms.

What gets disinfected and what gets sterilised?

The practical rule is what each item touches. Anything in contact with intact skin or with surfaces is disinfected: the couch, the armrest, the table, the outside of the handpiece, the lamp, the floor. Anything that works on the nail or close to the fold is sterilised: nippers, pushers, scissors, tweezers and the metal bits used in the handpiece. Anything that cannot reliably go through either process is single-use and is thrown away: cardboard files, orange sticks, buffing bands, towels.

Why does cleaning have to come first?

Because soil acts as a shield. A trace of filing dust, oil or cured product forms a film that steam cannot penetrate, and whatever is underneath survives the cycle. That is why instruments go first through a cleaning stage, usually an ultrasonic bath that shakes debris out of hinges and grooves, and only then are dried, pouched and sterilised. Skipping the first step invalidates the third.

What is the full sequence?

Seven steps, and the order is not negotiable. Cleaning, to remove all visible residue, usually in an ultrasonic bath. Disinfection, soaking the instruments for the contact time their data sheet specifies, which is what brings the microbial load down before they are handled. Drying, because trapped moisture interferes with the cycle. Individual pouching with its indicator. The autoclave cycle. Logging the cycle, which is what makes it checkable afterwards. Storage somewhere dry and closed until the moment of use, and within the expiry window the pouch manufacturer states. A UV cabinet sterilises nothing and does not replace a sealed pouch: at best it keeps a drawer clean. The pouch is opened in front of the person about to be treated, and not before.

How long does sterility last?

Until the barrier is broken, and not a minute longer. It is not a property the metal acquires; it is a condition of the pack. An intact, properly stored pouch keeps its contents sterile for months. A pouch that has been opened, wetted, torn or handled stops guaranteeing anything from that moment on, however spotless the instrument inside still looks.

What can a client actually check?

More than it seems, without asking anything technical. In this order:

1. The pouch arrives sealed, with no tears and no dampness.
2. The chemical indicator printed on it has changed colour, which shows the pack went through the cycle.
3. The pouch carries a sterilisation or expiry date, within the window its manufacturer states.
4. It is opened in front of the person about to be treated, and the instruments are not set down on anything that is not sterile.
5. Files, buffers and sticks come out of a new pack.

Beyond that, the sterilisation area can simply be asked for: in a place doing this properly it is not a hidden back room.

Sources: EN 13060, small steam sterilisers (CEN) · AEMPS · Cosmetic products (Spanish Medicines Agency)

Published: 12 October 2026 · Last reviewed: 12 October 2026