How to Tell if Eggs Have Gone Bad — and How Long They Really Last

You can buy a carton of eggs just about anywhere, including the supermarket, health food store, convenience store or gas station. And it's no surprise, considering they make an excellent source of inexpensive protein.

As with most protein sources, though, eggs can spoil, increasing your risk of developing food poisoning.

To avoid these symptoms (and frequent trips to the bathroom), read on to learn more about the safest way to handle and prepare your favorite egg dishes.

If you crack an egg and think it may be spoiled, the first thing to do is give the bowl a sniff. Generally, rotten eggs (whether cooked or raw) will give off an undeniable odor, signifying they're no good to eat, according to the Egg Safety Center.

Taking notice of the egg coloring can also help you discern whether your eggs are OK to eat. Another common egg bacteria is Pseudomonas, which can cause the egg white to appear pink, green or iridescent. If you come across a funky-looking raw egg, throw it out.

Sometimes, you may even come across an egg that has black or green spots, which means it may be growing fungus. In this case, you'll want to toss the egg and thoroughly wash your bowl and hands.

When it comes to rotten eggs, you're better off safe than sorry. So, if you're skeptical or unsure of how fresh your eggs may be, toss them in the trash and buy a new carton.

Eating mishandled or expired eggs puts you at a higher risk for Salmonella-induced food poisoning — which is no walk in the park.

A group of bacteria, Salmonella, is often responsible for food poisoning cases in the United States, according to the FDA.

Some people may develop symptoms of food poisoning just hours after eating the affected food, whereas others may take up to six days, according to the Centers for Disease Control and Prevention (CDC).

Salmonella infection can cause some unfavorable symptoms, including fever, vomiting, diarrhea and abdominal cramps, according to the FDA. Typically, food poisoning only lasts a few days and doesn't require medical assistance.

But in some cases, severe vomiting and diarrhea (several times a days for several days) can cause dehydration, requiring hospitalization. If your symptoms persist beyond two days, it's probably best to see a doctor to rule out any other issues and risks.

But if you handle and prepare your eggs properly, you can decrease your risk of ingesting any of this unwanted bacteria (more on that below).

The safety of your eggs starts with the decisions you make in the grocery store. Whether you buy standard, free-range, organic or pasture-raised eggs is up to personal preference.

But, there are things to watch out for.

Although it may seem like a no-brainer, you should only buy eggs if they're sold out of and stored in a refrigerator or refrigerated box, recommends the FDA. Then, before you add a carton to your cart, take a look at each egg, making sure that the eggs are clean and free of cracks.

You can also check the carton for a "sell by" date, however, egg processors aren't actually required to print and expiration date, according to the Egg Safety Center. However, cartons must carry a label that tells consumers what month, day and year the eggs were packed.

Before and after you handle raw eggs, you want to wash your hands, utensils and work surfaces with hot, soapy water, recommends the FDA.

Once you're done using the carton, toss the shells and put your eggs back in the fridge immediately.

Whether you take your eggs scrambled, poached or in an omelet, it's safest that you cook the egg until both the whites and yolks are firm, per the FDA. However, if you like a runny yolk, buy eggs that have been pasteurized or otherwise treated to destroy Salmonella.

Serve egg dishes immediately after they're finished cooking and avoid leaving cooked eggs or dishes out of the fridge for longer than two hours. The longer eggs stay out in warm temperatures, the more subject they are to bacteria.

If you're making deviled eggs for a later time, for instance, refrigerate the eggs immediately after preparation and serve them on small plates so they don't sit out.

Or, if you're packing hard-boiled eggs for lunch, make sure to transport them with an ice pack or in a cooler, the FDA suggests.