Are Grey Eggs Safe to Eat?

If you’ve ever prepared breakfast in the morning and cracked your boiled egg open only to find out that the yolk has turned gray, you’re probably close to freaking out. Don’t worry — even if this is the first time you’ve ever seen something like this, we’ve done the research for you to clear up any confusion. In this blog post, we discuss everything you need to know about this strange chemical reaction and answer the question, “is it safe to eat grey eggs?”

What are Grey Eggs? 

Even a perfect hard-boiled egg can take up a greenish-grey color around the yolk as a result of a chemical reaction between sulfur, present in the egg white, and iron found in the yolk. The two chemicals combine to create ferrous sulfide at the surface of the yolk. While this may be an unappealing color change, it’s not harmful and is safe to eat. 

This process takes place at 77°C within the ovalbumin. But over 70°C, the sulfur inside the egg whites forms hydrogen sulfide which reacts with the iron, forming iron sulfide, giving it a greenish gray color. You can stop the cooking process by running the eggs under cold water as soon as they’re cooked to bring the eggs to room temperature. 

How Do You Boil Grey Yolk Eggs? 

Iron sulfide in the egg creates gray or green rings around the egg, and will usually come out due to overcooking. According to the American Egg Board, the dry and crumbly yolk will take around 14 minutes to harden under boiling water. The best way to avoid overcooking your grey eggs is to place all the eggs in an ice bath as soon as they’re cooked. 

The ring around the yolk is created when hardboiled eggs are overcooked. To ensure that your grey eggs — even fresh eggs — will peel easily, gently place them in boiling water to shrink the albumen, then turn off the heat and cover them for eight to ten minutes. Next, plunge the large eggs into ice-cold water to shrink the albumen even more and get ready to peel them. 

The egg yolks will turn a  greyish green if they’re overcooked.

How to Know if You Have a Bad Egg 

You can find out if you have a rotten egg by filling a bowl with cold water and placing your eggs in it. If the eggs sink to the bottom of the bowl and are laid flat on their side then it’s fresh and safe to eat. Bad eggs will rise to the surface due to the big air cell which forms at the base — floating eggs shouldn’t be consumed and should be disposed of immediately. 

Should you notice grey eggs that stay at the bottom of the bowl but are standing on one end, it means that they aren’t as fresh as they could be but are still safe to eat. However, hard-boiled eggs are a bit harder to judge, so if you’re suspicious of their quality, be sure to do a smell test. If you notice that the smell is off, then it’s likely to have gone bad or is starting to — this test can be done for both boiled eggs and raw eggs. 

Why Do I Have a Dark Egg Yolk? 

The color of the yolk is determined by the diet of the hen it came from — those that were fed food with yellow-orange pigments will usually lay eggs with darker yolks. Because artificial coloring isn’t allowed to be mixed with chicken feed, some farmers will put marigold petals with feed to give yolks an orange color. However, the color of the yolk doesn’t have much to do with the nutritional content and is actually dependent on the pigments available in chicken feed. 

When a hen feeds on plenty of xanthophylls (yellow-orange pigments), they will create egg yolks with a darker orange hue. Darker yolks may also be the result of higher levels of Omega 3 in the hen’s diet, but there isn’t much of a difference apart from how it will look on your plate. Moreover, the yolk’s color won’t change in older eggs, so an egg with a dark yolk is still safe to eat. 

Are Dark Yolks Better? 

Darker egg yolks sourced from pasture-raised hens will often contain trace elements of fat-soluble vitamins. These may have been ingested as a result of a diet consisting of earthworms and bugs they may have foraged from grass. According to research done by the United States Department of Agriculture, the color of the yolk doesn’t have an effect on the nutritional value of the egg. 

Every yolk will have more fat, less water, and under half the protein found in egg whites. Moreover, the color of an eggshell won’t have an effect on its nutritional value and there is no difference between brown egg shells and white egg shells. Rather, the breed of the hen that produced the egg will determine the egg color. 

What Color is a Healthy Yolk? 

Generally, you’ll want your yolk to have a vibrant but dark color. Such yolks will typically be produced by hens raised in pastures where their diets consist of worms, fresh grass, and grasshoppers. This kind of diet will be rich in carotenoids, which give off the rich orange coloration. 

If by chance you encounter an egg with a white yolk, you’d probably be surprised. The good news is that they are perfectly safe to eat and won’t have much of a change in taste. This kind of color can appear light-yellow, to something paler, or completely white in color. 

If you notice any unusual signs of discoloration outside of the yolk such as iridescent, pink, or greenish egg white or yolk, these grey eggs should be discarded immediately. But eggs with a greenish-gray ring around a hard-cooked egg yolk are still safe to eat, according to the USDA. 

Can You Get Sick from Bad Eggs? 

Grey eggs that are contaminated with salmonella can induce food poisoning with varying symptoms that will usually appear between six hours to six days after eating the bad egg. Moreover, consuming food with harmful bacteria can cause foodborne illness one to three days after eating contaminated food. Typical symptoms of food poisoning as a result of salmonella include diarrhea and fever. 

A bad egg can still make you sick if it isn’t handled and cooked properly. This is because eggs can still be contaminated with salmonella or e.coli even if the egg is under high heat in a cast iron skillet. 

Are Eggs Safe in the Fridge? 

Eggs can be refrigerated for up to five weeks from the first day it was placed inside your fridge. When you see the sell-by date on the packaging, this will usually refer to the length of time that the eggs are perfectly fresh and safe to use. Be sure to purchase your eggs before the expiration date or sell-by date to ensure that you eat good eggs. 

Don’t Be Afraid of Grey Egg Yolk

Remember that the color of the yolk doesn’t indicate freshness, but egg whites can become more watery and “looser” over time. Even so, yolks won’t generally lose their color if they stay inside the fridge. The next time you cook eggs, know that there’s no need to worry about their color, as long as they don’t come with other signs of spoilage such as green spots. 

Sources 

• agrianswers.com
• thehealthyjournal.com
• interviewarea.com