What is the white goo in the middle of some hard-boiled egg yolks? My wife made some deviled eggs today, but found a surprise inside some of them after they were cooked. Right in the middle of the yolks was a tiny bit of some white goo, very different in color and consistency of the surrounding yolk.

What is this stuff? Was it safe to eat? We ended up tossing those eggs out because we had no clue.

UPDATE: my wife had taken a picture
This is so called white yolk, aka latebra, present in any egg, with slightly higher protein content. Its precise function is unknown; it is believed to be a center of the egg development. Perfectly safe.