It’s hardly surprising these days when news breaks that yet another food has sickened people across the country.
Sometimes, it's eggs. More than 1,600 cases of Salmonella enteritidis infection from eggs were reported in at least 10 states in 2010, the largest outbreak of this type of food poisoning ever recorded in the U.S. More than a half billion eggs were recalled.
Here’s a look at what went wrong at the henhouse—and what you need to know to eat eggs safely.
Which came first—the Salmonella or the egg?
The source of the 2010 outbreak was traced to two industrial farms in Iowa, where the barns were infested with rodents, flies and maggots, and filled with tons of manure, all of which can harbor or spread Salmonella.
Salmonella was detected in the feed given to young hens, in the water used to wash the eggs and elsewhere. One of the companies had already been cited numerous times over the years for unsanitary conditions and Salmonella contamination.
But how does Salmonella end up inside an egg? When Salmonella is in the environment, including feed, the bacteria can get inside the chicken. This doesn’t sicken the bird, but if Salmonella is in the ovaries or oviduct, the hen can pass the bacteria into her eggs before the shells form.
And if the eggs aren’t properly cooled, the bacteria multiply quickly. Eggs can be contaminated from the outside, too, since the shells have tiny pores through which Salmonella can penetrate. Thus, if the processing plant equipment is contaminated, or if workers have Salmonella on their hands, eggs can end up with the bacteria.