Recently, Jennifer Lovdahl of Anchorage, Alaska, posted images to her Facebook page of a Happy Meal she bought at the fast-food restaurant chain in 2010, which shows Chicken McNuggets and fries that don’t seem to have decomposed at all.
While certainly unsettling, the claims that McDonald’s food is laden with chemicals preventing it from rotting might not provide the whole picture.
First, let’s look at the many “experiments” that point the finger at McDonald’s. Much of the targeting may be traced back to Morgan Spurlock’s 2004 documentary Super Size Me, where, in an effort to examine the health effects of the fast food industry, he lived solely on McDonald’s food for one month (it wasn’t pretty). In one experiment, Spurlock aged a McDonald’s burger next to burgers from another restaurant. He did the same with french fries and left them in jars. While the burgers seemed to have rotted at the same rate, the fries did not.
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Let’s be honest: we all know fast food doesn’t provide you with the best sources of nutrients. But does that mean one type of fast food is any better than another?
“It’s very simple, really,” said Keith Warriner, a professor at the Department of Food Science at the University of Guelph in Ontario. “Our ancestors learned this: it’s all down to moisture.”
Whenever we grill a burger, fry potatoes, we’re removing that moisture, explains Warriner. “Microbes, yeast, mould, bacteria then can’t grow.”
In particular, Warriner said, when we grill a burger and fry potatoes, we’re removing most of the moisture. The same is said of a lightly toasted bun. So whatever small amount of moisture is contained within the meat and fries isn’t enough to help propagate bacteria and mould.
A similar conclusion was reached by J. Kenji López-Alt, managing director of Serious Eats, a site that examines the science behind food. López-Alt has conducted a few experiments based on the rotting burger. In his most recent experiment, he concluded that the McDonald’s burgers are small enough that they dehydrate at a rate that is too fast for whatever moisture is present to form mould.
But what about the McNuggets? Well, the McNuggets are also fried before they leave the plant, as you can see here in this YouTube video (as part of McDonald’s transparency campaign):
OK, so we’ve explained McDonald’s burgers, but what about other fast food outlets or even our own?
“There are more additives in a bread roll in a supermarket than in McDonald’s buns,” Warriner said.
READ MORE: What Canadians want to know about what’s in fast food meals
That’s because there’s a need to extend the shelf life of bread in supermarkets rather than the high turnover McDonald’s sees.
When it comes to making burgers yourself, we go back to López-Alt’s experiment. He was quite thorough: he tested a variety of scenarios including a homemade burger on regular bun and on a McDonald’s bun (he also included a Quarter Pounder). He weighed them, handled them with kitchen tools and carefully checked them for signs of mould over 25 days. His conclusions?
“Well, well, well. Turns out that not only did the regular McDonald’s burgers not rot, but the home-ground burgers did not rot either. Samples one through five had shrunk a bit (especially the beef patties), but they showed no signs of decomposition,” he wrote on his blog (his bold).
So it would seem that the moisture content and size both play a role in the rate of rotting food.