system
Given the following post, respond as if you're commenting on Reddit:
human
Where do the spores that cause mold on bread come from?

Are there spores in the bakeries where the bread is baked and they get in/on the bread before it is even packaged? Or are there spores living on my skin that are transferred onto the bread each time I open the bag to get a couple of slices? Or are they just floating around in my kitchen and each time I open the bread bag, some of that spore-bearing air ends up inside of the bag? Will an unopened loaf of bread still get moldy?

Also, some related questions:

Why do "name brand" breads (eg Wonderbread or Dempster's) seem to last forever without getting moldy (or even stale for that matter) while more "artisanal" breads produced by independent bakeries always go moldy in under a week, and "grocery store" breads produced by in-house bakeries at grocery stores seem to fall somewhere in between, usually getting moldy after 1-2 weeks? Is the difference in shelf-life of these different types of breads due to different preservatives being used, or does it have more to do with the environment in which the breads are made?

What is going on between the time a spore is first introduced to a loaf of bread and the point where the mold becomes detectable (either visually or by scent)? Is there ever a point where the mold is not detectable but still dangerous?
gpt
Mold is a fungi. It transfers from air to the bread.

Why industrial breads don’t get moldy so easily: tons of preservatives. Basically stuff that is poisonous to the fungi.

There are many types of possible molds, some more poisonous than others so what amount may cause problems depends. Some molds are completely fine (hence used in cheeses etc) whereas some can be very problematic in miniscule amounts. There are thousands of possible variations. When it smells bad, don’t eat it. When it is visible, don’t eat it (it is on the whole bread at that point since it’s porous stuff.