Why Does Food From McDonald's Never Seem To Rot?

Do you remember recently there was that picture of a six year old McDonald's meal that didn't look much different?

Here, I'll refresh your memory:

Pretty gross, right?

Why is it like that though? Is it so bad for you that it literally can't disintegrate? What's it doing to your insides? Well, try not to worry. It's pretty simple.

It's all down to moisture.

Dr Keith Warriner, programme director at the University of Guelp's department of Food Science and Quality Assurance, spoke to The Independent about the science behind it.

He said: "The reality is that McDonald's hamburgers, french fries and chicken are like all foods, and do rot if kept under certain conditions.

"Essentially, the microbes that cause rotting are a lot like ourselves, in that they need water, nutrients, warmth and time to grow. If we take one or more of these elements away, then microbes cannot grow or spoil food.

"In the example of a McDonald's hamburger, the patty loses water in the form of steam during the cooking process. The bun, of course, is made out of bread. Toasting it reduces the amount of moisture. This means that after preparation, the hamburger is fairly dry.

"When left out open in the room, there is further water loss as the humidity within most buildings is around 40%. So in the absence of moisture or high humidity, the hamburger simply dries out, rather than rot."

Well, there you go. It's not just Maccies either. Case closed.