blue mold; penicillium
Refers to the bluish-green mold commonly found on food, especially citrus fruits, and also to the genus Penicillium.
Blue mold has grown on the bread.
Some cheeses are made from blue mold.
blue cheese
Common mixed kanji-katakana spelling.
Katakana spelling, often used in scientific or emphatic contexts.
Kanji spelling using 黴 (mold), but the kanji is not a jōyō kanji and may be less familiar.
Compound of 青 (ao, 'blue') and カビ (kabi, 'mold'). The reading is straightforward.