Okay to Eat

A lot of food goes bad in my fridge while it's waiting for me to eat it. Sometimes it's an expensive block of cheese and more often things like carrots or celery. I buy this stuff thinking I'll change my diet and start eating healthier food if I keep it around, but it always ends up in the trash after I rediscover it in the back of my fridge four months after buying it. The other day I bought a piece of corn to add to my dinner, and when I got it home I found about half of it covered in a mysterious pink color. I have no idea what it was, but in general it's a bad idea to vegetables that are an unnatural color. So I treated it like I would a big hunk of cheese that had grown some mold, and I sliced off all the pink then cooked and ate it. What I need is a guide for what kinds of food are okay to slice off the nasty parts and still eat. I'm thinking about taking a piece of bread from my fridge right now and tearing off all the mold. It'd look like a piece of Swiss cheese, though I suspect it won't kill me if I toast it.