Upload & Sell: Off
Thing is...pretty much EVERYTHING has the spores in it. Yes, all those clean lenses you own has fungal spores in it. The key is not leaving it in conditions that will cause them to open and grow.
That is exactly what I think.
And it is very hard to clean something like a lens or camera body to get all those spores away.
Some time ago I talked with a Zeiss service guy. He told me that Zeiss had machines to make a good fungus cleaning, this equipment is no longer working. They have done a bit of fungus research back then.
My first lens with fungus was one I bought new, and I didnīt visited fungus "infected" lenses with that one. So the fungus spores where most likely not from a lens, but probably from humid environment of a farm :-)