I have. Multiple times. Oranges for the shrines.
A Shinto deity has intruded in the penguin's apartment and took those oranges for their own, noted.
That level of decay happens when food's been left for a long time. It rots, mold forms, and then when there's little left to break down I guess, it dies and dries out to form that grey-green dust you see on the table. Not great to be breathing that in if it's been sat indoors the whole time.
However, that long time also accounts for how long they were at the supermarket. I've seen newly bought oranges destroy themselves into green matcha matter in a dry clean environment within a week.
