雅虎新闻：为什么欧洲超市里的鸡蛋只放在普通货架上，而美国的鸡蛋则需要放在冷藏区？

Yahoo.com: Why is it that European eggs are stored on supermarket shelves while American eggs chill in the cold section?

The difference, experts say, has to do with the egg production process.

Unlike European eggs, American eggs are washed and sprayed with a sanitizer immediately after collection, then placed into a cooler. Bringing the eggs back to room temperature would increase the chance of bacterial growth, that's according to the USDA's egg grading manual.