Why doesn't McDonalds food decay for decades? What's in it?

most did except for french fries, Watch Super Size Me at the end

A lot of additives and preservatives.

It's not what's in it, but what isn't: water. 

McDonald's food has very littke water after cooking, so there is much less chance of decay.

Storing in containers keeps moisture out and also fungal spores.  

A lot of additives and preservatives.

Would never do that with other food but after seeing McDonalds food doesn't mold I figured it be safe to eat next day, its not! So strange.

It definitely decays within a day or two.

LOL! LOL! <LOL! You re RIGHT On here! I saw a five year old McD burger in a health food restaurant int he WINDOW! It had ZERO decomposition whatsoever. SCARY isn't it! And WE eat this stuff! TONS of preservatives. MAYBE it's just the PICKLE! WHO KNOWS  BREAD that isn't FRESH is NOT worth buying or EATING! It's FULL Of additives and sadly YEAST that is NOT healthy anymore! I STILL like their FIRES and sometimes MILK SHAKES!. Otherwise, YUCK!

The lack of water is mostly what keeps it from decaying.  It's not just McDonald's, I have a piece of rye bread that is around 15 years old and with no signs of mold or decay. 

You are mistaking McDonalds for packaged "Twinkies".  LOL

Things to pump you up and make you large.