It is quite hard to recognize an egg that had gone bad. Some of the eggs that you buy from store have best before date mentioned on the egg packaging but usually date is not mentioned which makes it hard for you to know if the egg is good or not. Here are some easy tips by following which you can recognize a bad egg.
If your egg lies on its side on the bottom of the bowl:
Your egg is still fresh.
If your egg sits upright but is still resting on the bottom of the bowl:
Your egg is on the older side, but still good to go.
If your egg floats:
Your egg has expired. If consumed, you could get food poisoning.
As an egg ages, some of the liquids of which it is composed evaporate into gas, and since eggs are very slightly porous, some of this gas escapes. The end result is that an old egg has slightly less liquid (because some has evaporated) and slightly more gas (because the liquid takes up less space) — which is consequently why old eggs float. New, fresh eggs have little or no air trapped inside their shells and therefore sink in water.
Older eggs, the ones that sit upright on the bottom of the bowl, though, are perfect for hard-boiled creations like egg salad or deviled eggs, because as the egg’s air pocket grows, it pulls away from the inside of the shell, making it much easier to peel.
For fried or poached eggs, fresher eggs tend to be the better choice because the whites have more structure; meaning that the white sits tight next to the yolk and isn’t as watery as an older egg. Test this for yourself: Crack an old egg and a new egg side by side. You’ll see that the newer egg sits taller and tighter than the older one.
Lastly, if you find that your egg white is slightly opaque and cloudy, don’t worry! This means the egg is still permeated with carbon dioxide from being laid and it is actually a sign of freshness.