All this is a long way of saying that egg producers have succeeded at reducing the rate of salmonella infection in egg-laying hens since the early 1990s. But there are other reasons salmonella infection is uncommon. Infected hens don’t always lay infected eggs—only rarely does the salmonella bacteria enter a hen’s ovaries and, consequently, its eggs. Using data from the 1990s, the Centers for Disease Control and Prevention estimate that one in 20,000 eggs is internally contaminated with salmonella. Since salmonella prevention practices have improved since then, the egg contamination rate is probably even lower now—indeed, according to Patterson, in Pennsylvania only 0.012 percent of eggs from salmonella-infected flocks are contaminated. That in and of itself probably explains why I’ve never gotten salmonella from raw eggs. (The fear that eggshells might be infected with salmonella even if the inside of the eggs isn’t is unfounded: The FDA requires rigorous egg cleaning, which means that any salmonella that might be on the shell of an egg—from infected hens’ fecal matter, for instance—is killed before the egg reaches a consumer.)
But let’s say an infected egg does make it into a consumer’s kitchen. If the egg is kept at or below a temperature of 45 degrees, the salmonella bacteria will have no opportunity to grow. (Most salmonella outbreaks are linked to restaurant settings, where large quantities of eggs are commonly mixed together and kept at unsafe temperatures—practices Patterson calls “egg abuse”—thereby giving bacteria a chance to spread from one egg to another.) If the amount of bacteria in the egg remains relatively small, it’s perfectly conceivable that a spoon-licker like myself would simply miss the infected portion of the egg, which would end up getting killed in the oven or washed down the sink.