What you see: A carton of raw eggs left out overnight
What it is: Unrefrigerated raw eggs that could be breeding grounds for salmonella
Eat or toss: This depends entirely on where in the world you are! If you’re in a country like the U.S. that typically refrigerates its eggs, then toss. If you’re in a country where eggs are sold and stored at room temperature, go ahead and eat. The safety difference lies in how the eggs were processed before they landed in your kitchen.
Let’s say you live in Boston. After a crazy, late night, you wake up in your Harvard Square apartment, looking forward to a breakfast of poached eggs. But when you get to the kitchen you are horrified to discover that the eggs you picked up yesterday are sitting on the kitchen counter, not in the fridge. You’re about to pitch them when you remember that lovely bed and breakfast where you stayed in Europe. They didn’t refrigerate their eggs at the Lavender Inn, you recall. In fact, you remember how intrigued you were when you learned that they kept them in a drawer. Perhaps, putting your own eggs in the fridge was just a silly, paranoid, American thing to do, you conclude, and you get out your pan.
This is when I leap out of the computer screen and tell you, “No! Don’t do it!”
Because, while it was perfectly fine and charming for the proprietors of the Lavender Inn to keep their eggs in a drawer, it’s a bad plan if you live in the U.S. The reason comes down to differences in regulations and processing, even though all countries have the same goal: to prevent salmonella, that hideous bacterial infection that can cause diarrhea, fever and abdominal cramps.
Salmonella can come from the chicken’s reproductive tract and land inside the egg, or it can hitch a ride on the outside via some feces that might have stuck to the egg. Everyone agrees on that. What they don’t agree on is the best way to process our eggs to avoid salmonella infection.
Eggs emerge from chickens with a natural protective coating, known as the cuticle or bloom. In Europe and other parts of the world, that coating is trusted to block bacteria and keep eggs safe at room temperature. In the United States, however, we’re concerned about other stuff, i.e. fecal matter and dirt, that might have landed on the egg shell, and so we've devised something like a car wash for eggs. They get scrubbed, rinsed, sprayed and dried, all at precise specifications tuned to minimize food safety risks. Yet, there are downsides to this sanitation process. First, if the temperatures aren’t right, the eggs’ pores may absorb some of the dirty water. Another drawback to being squeaky clean is that the eggs lose the natural defense provided by the cuticle and need refrigeration from that point forward. According to the American Egg Board’s Eggcyclopedia, about 10 percent of egg packers try to counteract the loss of the cuticle by coating them in edible mineral oil, but most American packers leave eggs a bit more naked than when they were laid.
A few other factors to consider: Some countries, including the United Kingdom, vaccinate their chickens against salmonella, which further cuts down their risk of the bacteria winding up on the egg. But this vaccination is not typically done in the United States. And while you might think there’s no harm in refrigerating the eggs either way, there is an argument in non-refrigerating countries that unwashed eggs shouldn’t be refrigerated at all because if they were ever removed from the cold environment for long enough, condensation could form and thus invite problematic bacteria to the party. Io9 reports that in some parts of Europe it’s even illegal to use the very egg washing facilities that are required in the United States. One thing that might help explain the difference in approach: Business Insider notes that with more chickens in smaller spaces on many U.S. farms, contamination on the egg's surface is more likely.
So, who has it right? It’s hard to know. You might even call it a what-came-first-the-chicken-or-the-egg problem. But the takeaway is that if you live in the U.S., your eggs should live in the fridge. And, of course, no matter where you live, you should cook your eggs to 160 degrees fahrenheit to make sure any salmonella that's somehow survived all this scrubbing or vaccinating, is finally killed.
Bloom - Eggcyclopedia -- American Egg Board
Glossary of Poultry Terms. College of Agriculture, Food and the Environment. University of Kentucky.
Americans why do you keep refrigerating your eggs?
Why Europeans don't refrigerate eggs
Here's why we need to refrigerate eggs. Los Angeles Times.
I left the egg carton on the kitchen counter overnight. Are the eggs safe to use? - Eggsafety.org
Why the US chills its eggs and most of the world doesn't - NPR
Safe Food Handling Tips - IncredibleEgg.org
U.S. should vaccinate poultry to stop killer salmonella
American eggs are so chill...