The age-old argument over the best way to cook the perfect boiled egg could be a thing of the past thanks to a new hi-tech ink logo going on shells.

After cooking begins, an invisible, temperature-sensitive thermochromic print appears in black to indicate when an egg is soft, medium or hard-boiled.

The eggs, developed by UK assurance scheme Lion Quality, will be sold in three different types of cartons.

The new logos will start to appear on eggs in the next few months. (Read more…)