By John Dodge

CHICAGO (CBS) — Does McDonald’s food actually rot?

A few years ago, while cleaning out the family car, I pulled up the rear passenger seat to discover a Chicken McNugget hidden underneath.

It looked pristine, and good enough to eat. I had no BBQ sauce handy, so I threw it in the garbage.

I honestly cannot tell you how long the food was wedged under the seat.

However, I do know it had been a long time–perhaps more than a year–since I had really deep-cleaned the car–beyond the cursory vacuum at the local car wash. Our family also didn’t eat at McDonald’s all that often.

Laura B., of Toronto, posed a question along those lines to the Oak Brook based fast food giant.

“How is it that a McDonald’s hamburger does not rot?”

The short answer is that it can rot, under the right conditions.

“There have been a lot of online videos and photos touting the fact that when left out for an extended period of time, a McDonald’s hamburger does not rot and that this is because they are laden with chemicals,” one of Canada’s top food scientists, Dr. Keith Warriner said.

“The reality is that McDonald’s hamburgers, French fries and chicken are like all foods, and do rot if kept under certain conditions.”

Microbes that cause rotting need water, nutrients, warmth and time to develop, Warriner said.

After the cooking process, McDonald’s hamburgers are actually quite dry. Plus, humidity inside most buildings is 40 percent or lower.

So without higher humidity, Warriner said, the food essentially dries up, rather than show signs of rotting.

As for Chicken McNuggets, McDonald’s produced a video in which a McNuggets fan buys a large quantity of cooked and frozen nuggets from McDonald’s restaurant and brings them to an independent lab for testing.

The results?

The tests showed that a McNugget is white chicken breast–debunking the fears that they are actually “chicken in a blender” or made with pink slime and filled with chemicals.

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