Among the most frequently-asked questions received via the Egg Safety Center hotline goes something like this: “I bought a carton of eggs at the grocery store but left them on the counter overnight. Are they still safe to eat?” The reply generally goes something like this: “It’s better to be safe than sorry … you should toss those eggs out.”

In the United States, it’s more than a food safety recommendation that eggs be refrigerated – it’s the law. The U.S. Department of Agriculture (USDA) determined that the best way to fight salmonella contamination is by making sure eggs are squeaky clean before they reach the consumer. So, on commercial egg farms it is required that eggs are thoroughly washed and immediately refrigerated before they leave the farm. The washing process removes any contaminants, such as manure, with which the eggs may have come in contact. But, it also removes the natural coating of the egg, leaving the shell porous.

It’s a different story in Europe where authorities approach the threat of salmonella quite differently. Eggs there are not required to go through extensive washing, which leaves the natural coating on the egg. Because this coating remains on the eggs, authorities feel it is safe for them to be sold at room temperature. In some European countries, salmonella prevention is based in vaccinating hens.

In America, food safety officials emphasize that once eggs have been refrigerated, it is critical they remain that way. A cool egg at room temperature can sweat, facilitating the growth of bacteria that could enter the egg through its porous shell.

Marianne Gravely, who has been answering consumer food safety questions at the USDA for the better part of three decades, addresses the issue this way:

“Eggs shouldn’t be left at room temperature for more than two hours. There is no way to know if a shell egg is pathogen-free. Food poisoning bacteria don’t affect the taste, smell, or appearance of a food. You can’t tell if a chicken is infected with salmonella, so any egg, whether it came from a grocery store, a farmers market, or from your neighbor’s backyard hens, could contain salmonella.”

Another important way to address salmonella concerns is through proper cooking. Eggs should be cooked until both the whites and yolks are firm. Casseroles and other dishes that contain eggs should be cooked to at least 160°F. What if you like eggs with runny yolk or are preparing a recipe requiring raw egg? Use pasteurized eggs, which have been heated to a temperature that kills bacteria, a choice recommended by the Food and Drug Administration, especially when cooking for the elderly, the very young, or anyone with a compromised immune system.

So, washed or unwashed; refrigerated or room temperature — which process is best for keeping eggs safe? Vincent Guyonnet, a veterinarian and scientific adviser to the International Egg Commission put it this way: “They’re different approaches to basically achieve the same result. We don’t have massive [food safety] issues on either side of the Atlantic. Both methods seem to work.”

Eggs are an important source of protein and a key component of a healthy diet. Egg farmers work hard to comply with all federal and state regulations, understanding the importance of food safety in delivering safe, wholesome eggs to stores and restaurants.

Visit the Egg Safety Center for more information about the safe handling and storage of eggs. United Egg Producers support the Egg Safety Center as a resource for consumers and food service.