Who has cut mold off bread and continued to eat the "non-moldy" part? I'll admit I have done this before. Sometimes money is tight and you have to do what you have to do. I mean come on! You just bought the bread what feels like yesterday! It is only on one slice too! This is where many of us have had the misconception that if mold is only on one slice of bread you’re okay. Mold in bread can spread very easily compared to other foods like cheese. With that being said that means just because you cut off what you can see; that does not mean the roots of the mold have not spread to other parts of the bread.
Why should you worry about it?
Well you do not have to “worry” but you certainly do not want to eat bread after it has been moldy. Many will say “Well penicillin comes from mold so it is okay.” While that is true, you do not know what mold is on your bread. There are hundreds of thousands of molds in the world, that is not very good odds. In the end, trying to save yourself a couple dollars could cost you more if you get sick.