Is It Cheese?

Something very strange is happening inside my refrigerator right now. In fact, it is bothering me to no measurable end. See, I am a fan of dairy products. A big fan of dairy products. I go through a gallon of milk in three days, a brick of cheese is lucky to make it a week, yogurts are gone 15 days before they expire (for those who don't shop for yogurts often, that's about 3 days after I buy them). I am in fact such a large fan of dairy that I have stopped taking my medication simply because it won't let me eat or drink dairy products 2 hours before or after consuming the medicine.

It is this love for dairy that has led me to my strange discovery, and it is my love for cheese that worries me so much about this current mystery. What has happened is this. I have been living in this apartment for five weeks now. On my first day moving in, I filled the fridge. Amongst my purchases were Kraft American Singles and a brick of Kraft Sharp Cheddar. It turns out I don't like Kraft Sharp Cheddar, so it ended up sitting in my fridge until it grew mold. That took about a week. Here's the mystery. The Kraft Singles have been sitting in there for five weeks as of today, and they don't have a single freckle of mold forming anywhere on them!

I noticed this two weeks ago, and so to speed up the process, I took a single out of the wrapper and left it on the bottom shelf. Nothing happened. No mold, no condensation, nothing. It is just a piece of cheese sitting on the bottom shelf of a fridge. Last week I bought more cheese (Crackerbarrel sharp cheddar if you are interested). I cut a small square off and placed it on top of the Kraft single. The Crackerbarrel had mold growing on it within three days. Today, the whole square is nice and moldy. Here's the best part. The mold stops the second it gets to the Kraft Single!

What the hell are Kraft Singles made out of?! It can't possibly be dairy, because if it were, mold wouldn't be so scared of it. It isn't cheese, that much is certain. I mean, it doesn't even really taste like cheese. It's orange, but that's about the only parallel I can draw. So if it isn't dairy, and it isn't cheese, what is it?

See, it's a mystery. Help me solve it. Help me discover the truth about Kraft Singles. I'm already looking into whether or not they were produced by aliens- pick a hypothesis, and research into it. This problem needs to be solved!