Often when I’m handing over a dozen eggs to a new egg customer, they ask me how long my eggs can be stored before they ‘go bad’. This opens up a rabbit hole of other questions and bits of information people are likely not to know about with respect to storing, washing, keeping, and eating eggs.
How long do eggs last? Well, it depends upon where you get them from, how long they’ve been there, and how they were treated before they come into your kitchen.
Obviously most egg consumers, at least in the US, buy their eggs from a grocery store. Because of the outbreaks of food poisoning due to the bacteria Salmonella Enteritis found in a small percentage of grocery store eggs, the US FDA “Egg Safety Rule” went into effect July 9, 2010 for egg producers with 50,000 or more laying hens. In 2018, the FDA updated its page on egg safety. It recommends following practices much more conservatively than ever before with respect to selling, buying, storing, and eating eggs. In 2018 the US FDA revised the publication.
A special segment written for the consumer is found on the FDA Resource page, found here: https://www.fda.gov/food/resourcesforyou/consumers/ucm077342.htm , but here is a summary:
You can help keep eggs safe by making wise buying decisions at the grocery store.
- Buy eggs only if sold from a refrigerator or refrigerated case.
- Open the carton and make sure that the eggs are clean and the shells are not cracked.
- Store promptly in a clean refrigerator at a temperature of 40° F or below. Use a refrigerator thermometer to check.
- Store eggs in their original carton and use them within 3 weeks for best quality.
Proper storage of eggs can affect both quality and safety.
- Use hard-cooked eggs (in the shell or peeled) within 1 week after cooking.
- Use frozen eggs within 1 year. Eggs should not be frozen in their shells. To freeze whole eggs, beat yolks and whites together. Egg whites can also be frozen by themselves.
- Refrigerate leftover cooked egg dishes and use within 3 to 4 days. When refrigerating a large amount of a hot egg-containing leftover, divide it into several shallow containers so it will cool quickly.
Clearly these recommendations, and the laws that large-farm egg producers must follow, are very conservative. Egg safety appears to be a precise and daunting, sometimes confusing business. Especially since cartons found in stores, which usually contain both a “Best By” (cannot be more than 45 days past the packaging date) and a “Sell By” date (cannot be more than 30 days past packaging date), are not clear on how many days it took for the egg to be packaged after it was actually laid. The accuracy of exactly thirty days as a “sell by” reference, and 45 days as a “use by” reference is kind of irrelevant if an egg could be packaged anywhere from 1 to 2 to X? days after it’s laid.
So what’s the bottom line? When buying eggs from the grocery store, put them in the fridge and try to use them up in 4 to 5 weeks time. If you’re not going to eat them within that time, consider hard-boiling or freezing them (without the shell). Here you can find how long do hard boiled eggs last.
Buying eggs from a local, family farm or small egg producer, or of course raising your own hens is a whole different ballgame. Why? Well, of course because you probably have a much better chance of getting a truly ‘fresh’ egg from one of these avenues. In fact, eggs that have been brought in from the coop, unwashed, which is the key, can easily sit outside the refrigerator for a 4 weeks or a month before eating. Chicken eggs are naturally laid with a coating, called a cuticle, on the shell that serves as a barrier against bacterial contamination.
This cuticle that coats a fresh egg shell is mainly composed of protein, and is also very rich in phosphorus. Albeit thin, the mighty cuticle limits movement of particles, water, and bacteria through the shell pores (Board and Halls, 1973; Board and Tranter, 1986), and winds up being the most important chemical defense of the eggshell against most or all bacterial penetration.
Ironically, the amazing natural coating on a fresh egg is all but destroyed by the very thing we do in order to try and make the egg cleaner: by washing. This is why, when I take my freshly laid eggs inside from the coop, and I plop the eggs in a basket on the counter, they can stay that way for literally weeks and still be wonderful to eat. The coating on the egg has not been disturbed, and is doing its job protecting the inside yolk and white from spoiling by bacteria. When I’m inclined to eat or use one of my eggs for cooking, I may wash an egg if it’s very dirty, but if I do, it’s only just before use.
Eggs from your grocery store have all been put through a wash process, and since this process destroys the natural cuticle, the eggs must then be refrigerated to prevent any lingering bacteria from easily entering and contaminating the egg. For this reason, store bought eggs must be kept in the fridge.
Want to figure out if your egg is fresh? An easy way is to perform the “Float Test”. As time goes on and an egg ages, moisture and carbon dioxide evaporate from the shell’s pores, and air is allowed to seep in. This creates an air space between the shell and the white. The older the egg, the larger the air space. Putting a questionable egg in a bowl of water and noting the buoyancy, how well it floats, tells you how big the air space is. The older the egg, the larger the air space, the better it floats. A telltale fresh egg is one that has sunk to the bottom.
How Long Can Fertilized Eggs Last?
I find it truly amazing that so many adults have no idea if a rooster must be present in order for a hen to lay an egg in the first place.
Just like human females, hens release eggs on a regular basis. When fertilization of an egg, be it human or hen occurs, then the result is exactly what you would expect: if the fertilized egg is allowed to gestate, a baby will be made. If in fact, there is no fertilization…in a hen’s case that would mean no rooster has been allowed to mate with her, then the hen lays an egg with absolutely no chance of a chick coming out of it. If the egg has been fertilized, and all goes well as far as temperature goes, a chick will emerge from the egg in approximately 21 days. If the fertilized egg is promptly refrigerated after being laid, on the other hand, it will remain just an egg and is otherwise identical to a non-fertilized egg in appearance and flavor. Absolutely 100% fine to eat.
Chances are, small farms with roosters and hens mingling together have many eggs fertilized on a regular basis. Unless, however, these eggs go for over a week under perfect temperature conditions (99-102 degrees Fahrenheit), there should not be concern over having a chick form inside the egg. Again, they are perfectly fine to eat.
Good Eggs and Bad Eggs
At the end of the day, ‘bad eggs’, while potentially dangerous to human consumption, are few and far between. The USDA and responsible egg handling, combined with the egg’s natural defenses against bacteria have done a good job keeping bad eggs in check. As normal practice goes, good eggs and bad eggs are readily discernible, even if only by smell.
Not so much maybe with the good eggs and bad eggs of the human kind, but that is another topic for another day.