A reader asks: “Why do Americans refrigerate their eggs?”
Kim Severson, a food reporter for The Times, considers the question.
Americans love refrigeration, and eggs are high on the list of items we rush to get into the refrigerator after a trip to grocery store. Meanwhile, our culinary compatriots in Europe, Asia and other parts of world happily leave beautiful bowls of eggs on their kitchen counters.
So what gives?
Mostly, it’s about washing. In the U.S., egg producers with 3,000 or more laying hens must wash their eggs. Methods include using soap, enzymes or chlorine.
The idea is to control salmonella, a potentially fatal bacteria that can cling to eggs. The Centers for Disease control estimates that salmonella causes about 1.2 million illnesses a year, resulting in 450 deaths — though not all of those cases are traced to eggs.
The bacteria can be passed through the porous shell to the inside of the egg from material on the outside, though in rarer cases it can infect the ovaries of a chicken and infect the eggs from the inside.
Why the 3,000-hen cutoff? Salmonella outbreaks are more prevalent in large operations where the chickens are kept in close quarters, often in cages stacked on top of one another. Some large-scale producers vaccinate their flocks, but not all. Thus, the one-size-fits-all washing regulation.
But — and here is the big piece of the puzzle — washing the eggs also cleans off a thin, protective cuticle devised by nature to protect bacteria from getting inside the egg in the first place. (The cuticle also helps keep moisture in the egg.)
With the cuticle gone, it is essential — and, in the United States, the law — that eggs stay chilled from the moment they are washed until you are ready to cook them. Japan also standardized a system of egg washing and refrigeration after a serious salmonella outbreak in the 1990s.
In Europe and Britain, the opposite is true. European Union regulations prohibit the washing of eggs. The idea is that preserving the protective cuticle is more important than washing the gunk off.
At most American farm stands and farmers’ markets, eggs are sold unrefrigerated. And many cooks store unwashed eggs from small producers on their counters, washing them just before they use them — or not at all, if they are getting dropped into boiling water.
However, if you buy farm eggs chilled, it’s better to keep them chilled. Bringing them to room temperature if you’re not going to cook them right away can cause condensation, which can damage the cuticle or encourage mildew. A refrigerated egg, no matter the source, will be good for four or five weeks. Unrefrigerated eggs are best used within a week, though they may be fine for two.
Safety concerns aside, room-temperature eggs perform better in the kitchen. If cold eggs are worked into batters with a high fat content, they can reharden the fats, and you’ll end up with batter that looks curdled and whose texture could be impacted. Also, if you want more volume when you whip egg whites for meringue or soufflés, use room-temperature eggs.