This recent post by Jennifer Lovdahl has been shared about 350,000 times on Facebook:
It's been 6 years since I bought this "Happy Meal" at McDonald's. It's been sitting at our office this whole time and has not rotted, molded, or decomposed at all!!! It smells only of cardboard. We did this experiment to show our patients how unhealthy this "food" is. Especially for our growing children!! There are so many chemicals in this food! Choose real food! Apples, bananas, carrots, celery....those are real fast food.
It's been argued that cases like these mostly depend of food quickly getting dehydrated, stopping microbial growth. But for some reason that's usually not what happens to real food I leave lying around.