system
Given the following post, respond as if you're commenting on Reddit:
human
Why do I need to store my eggs in the refrigerator? How come they go bad when they're stored outside of the cold?
gpt
Eggshells are porous. In their original form, they're covered in a waxy cuticle as the last stage of development before emerging from the hen. Incidentially, this is how salmonella gets into eggs - if the hen is infected, the egg will be as well, and the cuticle will seal the bacteria in.

Commercial processed eggs have the cuticle washed away, and replaced with food-grade wax. However, this still isn't a perfect seal, and over time there can be migration of gases across the shell, leading eventually to spoilage of the egg. Cold temperatures help slow this process even further, while room temperatures can degrade the wax coating, hastening the eventual decline.