How McDonald's fries are tested

In an age of social media and hyper-informed consumers, the world's largest burger chain is being forced to open up about the provenance of its beef, potatoes and more.

After eighty minutes of testing, a winner was declared: Lamb Weston, which, for the second time in a row, had triumphed with a sample from its American Falls, Idaho, plant. The final score was 95 out 100 points - showing there was still room for improvement.