Cotton Bags

How/Why do plastic and paper bags prevent mold?

I am doing a science fair project on what types of bags prevent mold the longest and we need to know how or why plastic and paper bags prevent mold (at least to the extent that they do). Our guess so far is that plastic eliminates more humidity and dust from the air that can cause mold spores to grow. Paper bags do that too only they are not sealable, allowing more moisture in. Is this even close or is there anything to add? Thanks so much!

Public Comments

1. Baked goods mold fastest in warm and moist environments, making a room temperature kitchen particularly inviting for fungi.
2. more than just moisure is kept out. the most important thing that is kept out is oxygen. without it bacteria cannot thrive and it is in very low supply then its very hard for it to form in the first place. this is why vaccum sealing is now being used. it removes ALL the oxygen.
3. I know plastic isn't a naturaly occuring material on Earth, so mold can't feed on something that isn't organic. That is why plastic is hard to breakdown or decompose. Paper though is made from trees/plants and when wet and put in a dark room for a week, will have mold. Mold is on everything but needs hot/warm, humid, and dark conditions to grow.