Disinfected blister I left to shrink (7)

I believe the answer is:

sterile

I'm a little stuck... Click here to teach me more about this clue!

'disinfected' is the definition.
(sterile can mean clean or disinfected)

'blister i left to shrink' is the wordplay.
'STERILE' is hidden in amongst the letters.
However, I am uncertain how this is indicated.

Can you help me to learn more?

(Other definitions for sterile that I've seen before include "Uninspired" , "Ineffective" , "Barren" , "Antiseptic" , "Aseptic or infertile" .)

I've seen this clue in The Times.

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