The real reason McDonald's once recalled a million McNuggets

Every so often there's a scandal that makes waves in the fast-food world. Remember pink slime, the "lean, finely textured meat" (via NPR) with an unnatural artificial tint to it that was used for years by burger chains until McDonald's announced it would no longer use the product (via ABC)? After the McDonald's announcement in 2012, other restaurants followed suit.

Invariably, every couple of years someone finds a finger found in a fast food meal and the occurrence is so frequent that it prompted NPR to write an article called "A History of Human Fingers Found in Fast Food" back in 2012.

Also buried somewhere deep in your brain may be the story of McDonald's recalling a million Chicken McNuggets a few years back. If you're a McNugget fan, you can rest easy as the reason for the recall wasn't quite as gruesome as other fast food missteps. Still, it involves finding a surprise in a piece of food ordered at a restaurant, which is never a pleasant experience.

Mysterious plastic pieces make their way into McNuggets

In 2015, McDonald's Japan apologized to customers after a diner found pieces of plastic in their McNuggets (via Mother Jones). To try and remedy the problem, the chain decided to recall almost a million nuggets from the factory in Thailand where they were produced. The factory in Thailand issued a statement saying that they were confident that the piece of blue foreign material did not originate from their production facility. However, even after the recall, a second diner in Japan found a piece of vinyl in an order of McNuggets. The whole thing was never solved and it went away as quickly as it came.

In any event, finding a non-human-product in the food must have been a more pleasant experience than a diner in Osaka, Japan, who found a piece of a human tooth in an order of french fries.

The bad press did not help the company's sales, to say the least. Sales numbers dropped more than 10 percent compared to the year prior and the company had their first net loss in Japan for over a decade.