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 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.
Japan also standardized a system of egg washing and refrigeration after a serious salmonella outbreak in the 1990s.
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.
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.
(The cuticle also helps keep moisture in the egg.)
Why Do Americans Refrigerate Their Eggs?’ -
Ask The Times, a Times Insider feature, draws on New York Times expertise to answer questions submitted by you, our readers.
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 idea is that preserving the protective cuticle is more important than washing the gunk off.