How do you know if eggs are bad?
You may see visual cues, such as a liquid consistency in the egg white, scientifically known as albumin, or discoloration (bacterial contamination can cause the albumin to turn a greenish or opalescent color). Throw it away! Note that a spot of blood on the yolk is perfectly normal – it’s caused by a ruptured blood vessel. Properly cooked, the egg is safe to consume.
If you open the carton and find that one of the egg shells is cracked, it’s best to throw the egg away. Cracks in an eggshell, no matter how small, provide an opportunity for bacteria to enter the egg, speeding up the spoilage process. Here’s the golden rule: when in doubt, throw away the maybe rotten egg. Prepare oatmeal and get on with your day.
Note that there is a difference between everyday bacterial spoilage and Salmonella contamination. “Usually, it’s not the pathogens” — like salmonella — “that make food look or smell disgusting,” says Dr. Conductor. “It’s the corrupting organisms. They won’t make us sick, but they will make the food unappetizing.”
Will eating an older egg cause food poisoning? Probably not, but it probably won’t taste very good either. The real danger lies in the salmonella bacteria, which are imperceptible in terms of taste, smell and appearance.
Here’s the bad news: Salmonella is only detectable under a microscope, so there’s no way for the average person to know if their egg is infected. “Just because the egg looks and smells good doesn’t mean it doesn’t have salmonella,” warns Dr. Conductor.
The good news is that only about 3 eggs in 10,000 may contain Salmonella in the egg white, so the chance of contaminating your carton is pretty low. If you do end up with one of those bad eggs, there are precautions you can take to curb bacterial growth.
Salmonella live in the albumen (or albumen) of an egg, where a number of natural preservatives keep the bacteria in check. But as an egg ages, the yolk membrane that separates the albumen from the yolk begins to break down. Over time, salmonella bacteria can invade the yolk where it can spread. This means that as an egg ages, the risk of salmonella multiplying increases – but there are some steps you can take to help protect yourself. The most important factor? Temperature.
“The lower the temperature, the slower the breakdown of that yolk membrane. Salmonella can no longer multiply below a certain temperature,” explains Dr. Conductor. Make sure your refrigerator is set to 40°F or lower to prevent the spread of pathogenic bacteria.
Note that cooking an egg with salmonella at a temperature of at least 150°F will kill the bacteria. With proper handling, even a contaminated egg can be used in baking or other applications where the whole egg is cooked through (i.e., no runny yolk).
To maintain the shelf life of your eggs:
Stored properly, 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 help extend the life of your eggs.
Choose your box wisely.
Brands aren’t required to print the use-by or expiration dates on their eggs, but if they do, they have to follow a few rules. According to the USDA, if an expiration or best-before date is listed on the carton, it “cannot be more than 30 days from the day the eggs were packed in the carton,” while the use-by or best-before date can be 45 days from the Egg packing date. By paying attention to these labels, you can tell which eggs are the freshest in the aisle.