Maybe you’re seeing visual cues, like a runny consistency in theegg whites, scientifically known as the albumen, ordiscoloration (bacterial contamination might cause the albumen to turn a greenish or iridescent color). Trash it! Note that if you see a blood spot on theegg yolk, that’s completely normal—it’s caused by a ruptured blood vessel. Cooked properly, the egg is safe to consume.
If you open up the carton to find that one of theeggshells has cracked, it’s best to discard that egg. Cracks in aneggshell—however small—open up an avenue for bacteria to get inside the egg, accelerating the process ofspoilage. Here’s the golden rule: When in doubt, toss the maybe-rotten egg out. Make someoatmeal and get on with your day.
Note that there’s a difference between everyday bacterialspoilage andsalmonella contamination. “It’s typically not the pathogens”—likesalmonella—“that cause foods to look or smell gross,” says Dr. Schaffner. “It’s thespoilage organisms. They’re not going to make us sick, but they make the food unappetizing.”
Will eating anolder egg give youfood poisoning? Probably not, but it probably won’t taste very good, either. The real danger lies in thesalmonella bacteria, which is not perceptible by taste, smell, or appearance.
Salmonella
Here’s the bad news:Salmonella is only detectable under a microscope, so the average person has no way to know if their egg is infected. “Just because the egg looks and smells okay doesn’t mean thatsalmonella is absent,”Dr. Schaffner warns.
The good news: Only about three out of every 10,000 eggs might containsalmonella in the albumen, so the chances of your carton being contaminated are quite low. Still, in case youdo have one of thosebad eggs, there are precautions you can take to curtailbacterial growth.
Salmonella lives in the albumen (or whites) of an egg, where a number of natural preservatives keep the bacteria in check. But as anegg ages, the yolk membrane—which separates theegg white from the yolk—starts to break down. Over time,salmonella bacteria may be able to breach into the yolk, where it’s able to run rampant. This means that as anegg ages, the risk ofsalmonella multiplying increases—but there are a few steps you can take to ward against this. The most important factor? Temperature.
“The lower the temperature, the slower the breakdown of that yolk membrane. Below a certain temperature,salmonella won’t be able to grow,” explainsDr. Schaffner. To discourage the spread of pathogenic bacteria, make sure your fridge is set to 40°F or lower.
Note that cooking an egg with salmonella to a temperature of at least 150°F will kill the bacteria. When handled properly, even a contaminated egg can be used in baking or other applications where the entire egg will be cooked through (i.e. no runny yolks).
How to preserve the shelf life of your eggs:
With proper storage, eggs should last for weeks in your fridge. But there are a few precautions you can take to keep your eggs fresher for longer. Here are a few shopping tips and other recommendations to prolong the life of your eggs.
Choose your carton wisely.
Brands are not required to print use-by orexpiration dates on their eggs, but if they do, they have to follow a few rules. If the carton lists anexpirationorsell-by date, it “can be no more than 30 days from the day the eggs were packed into the carton,” according to theUSDA, whereasuse-byor best-before dates can be 45 days from the eggs’pack date.Paying attention to these labels can help you determine which eggs in the aisle are freshest.
