Why McDonald's food rots (despite what social media wants you to think)

Videos and images of fast food 'not rotting' prove highly popular on social media

As Claire Varin placed it in front of the man, a member of staff brought over another meal and apologised to him for the wait (Scott Olson/Getty Images)

A picture of a McDonald’s Happy Meal, apparently made in 2010, has been widely circulated on social media as a "warning" against fast food.

Jennifer Lovedahl from Anchorage, Alaska posted the photo on Facebook earlier this month which showed the meal along with a receipt dated at roughly midday on 8 January 2010.

"It’s been sitting in our office this whole time and has not rotted, molded [sic], or decomposed at all!!!” she wrote. "It smells only of cardboard."

Videos and images of fast food "not rotting" prove highly popular on social media.

One chiropracter in Michigan has been saving a Taco Bell chicken taco and McDonald's cheeseburger for two years, while an enterprising hostel has a live video stream where you can watch the "last McDonald's hamburger in Iceland" rot - or not - on video.

So, what is this apparent love of non-rotting food? Is it a desire to prove that McDonald's food is bad for your insides?

McDonald’s FAQ section already addresses issues of its food not seeming to rot, explaining that “food needs moisture in the air for mould to form."

And Dr Keith Warriner, programme director at the University of Guelp’s department of Food Science and Quality Assurance, has explained further: “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.”

Food blog A Hamburger Today conducted an experiment to confirm that this phenomenon of non-rotting burgers was not unique to McDonald’s.