Sterilized
Sterilised, Pasteurised, Pasteurized
Someplace with nothing amounts of bacteria is sterilized.
むきん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
Tofuguのステッカーが無菌かどうかの問い合わせのメールが来たんだけど。
I just got an email asking whether or not the Tofugu stickers are sterilized.