When we walk into grocery stores in the United States to buy eggs we almost always pull them from a refrigerated cooler. But the cold storage we use here isn’t used in other parts of the world. The reason, which seems a bit counterintuitive, is that in the United States we wash our eggs. As Hank Green of SciSho explains, when producers wash eggs in the United States, in addition to cleaning the egg it removes a layer of protein called the cuticle. The cuticle protects eggs from bacteria that could permeate the shell. In many European countries, egg washing is illegal, so the cuticle is protected. Between the cuticle and vaccinations for egg laying hens, eggs don’t require a chilled environment for protection from salmonella or other harmful bacteria. So if you’re across the pond and see egg cartons sitting out at room temperature, don’t worry. They’ve taken other precautions. Check out the video above for Green’s full explanation.