Why do we refrigerate our eggs in the U.S.? According to the FDA, it’s because they’re washed — in fact it’s the law in America. The goal is to protect against salmonella since there is a chance the eggs will have fecal matter on them. If that fecal matter is contaminated, salmonella could spread through the shell to the inside of the egg. The FDA hypothesizes that salmonella contaminated eggs lead to 79,000 cases of foodborne illness and 30 deaths a year.
But in places like the UK, egg washing is actually against the law because they believe this washing method does more harm than good. When you wash eggs, a natural protective material, called the protective cuticle, is removed. The cuticle is supposed to block bacteria, plus all hens are vaccinated against salmonella in the UK, so there’s a low threat of it being present on the outside of the egg.
The U.S. doesn’t require farmers to vaccinate their hens, which leads to a greater chance that salmonella will be present. The UK also prefers free-range methods, whereas it’s more common in the U.S. to see large facilities, where hens are crammed in one area, and disease spreads more easily. After American eggs are washed, they are sanitized and immediately refrigerated. Once they’re cooled down, they have to stay cool, otherwise they sweat — which can also cause bacteria.