No one wants to be — or worse, eat! — a rotten egg. You might not necessarily get salmonella from bad eggs, but according to Emily Rubin RD, LDN at Thomas Jefferson University Division of Gastroenterology and Hepatology, they can be the cause of some pretty uncomfortable digestive symptoms like cramps and diarrhea. Plus, of course, they taste terrible. So, how can you tell if a raw egg is still good? There are five ways to tell.
Check the pack date.
The United States Department of Agriculture does not have a federal regulation requiring eggs to have a sell by or expiration date. However, cartons of eggs with the USDA-grade shield — which indicates the eggs have been graded according to quality — are required to have a "pack date." This date is a 3-digit code where 001 indicates Jan. 1 and 365 is Dec. 31. According to the USDA, eggs stored in the refrigerator will last between 4-5 weeks after this pack date. So, even if your eggs do have a sell-by or expiration date, they're often still good and safe to eat as long as they are consumed within 5 weeks of the pack date.
Does it smell bad?
According to Rubin, using your sense of smell is the most reliable method of checking to see if an egg is still fresh. She recommends smelling every egg immediately after cracking it and before using it. If it's bad, it will have a "distinct foul odor." Even if you didn't get a good sniff prior to placing it in your pan, you're probably OK.
"There's a good chance the smell will still be present when the egg is cooked," Rubin told TODAY Food. But don't count on your nose being able to tell you whether or not an egg is infected with bacteria. "If an egg contains salmonella, it may pass all the fresh tests because they do not usually smell or taste bad," she said.
Does it float?
While it's common knowledge in the kitchen that fresh eggs sink and lay on their sides, eggs that stand on end or float aren't necessarily bad — they're just older. As eggs age, it's believed that they lose moisture through their porous shells, and the amount of air they contain inside increases, making them more buoyant. If your eggs float, it's still best to crack them and smell them to determine if they're still good.
Does it sound fishy (or swishy)?
Much like you can shake a lightbulb to hear if the filament is broken, some people say you can also shake an egg to hear if an egg has gone bad. The theory is that, when shaken, fresh eggs will make no sound, while not-so-fresh eggs will sound like the liquid inside is sloshing around. This noise indicates the yolk and/or albumen (egg white) is less firm. However, it's worth noting that this method is questioned by experts like Don Schaffner, PhD, a food scientist at Rutgers University, who told SafeBee, "this sound test has no credibility."
Does it look funny (or runny)?
Of course, the best way to tell if the egg's inside is less firm is to look at it. Crack the egg in question into a bowl or pan and, if the albumen spreads out a lot, it's generally an older egg. Still, old doesn't necessarily mean bad. As Rubin says, it's best to smell it to determine that. The color of the yolk also doesn't necessarily indicate freshness either; rather, egg yolk color hints at the diet of the chicken that laid it. The egg yolks of chickens fed corn or wheat will be lighter than the yolks of chickens fed plants with more yellow and orange pigments.