Eggs are nutritious and affordable, but they are still perishable and can spoil if not stored properly. To reduce the risk of foodborne illness, it’s important to check eggs before and after boiling. Before cooking, try the simple water test: place the raw egg in a bowl of cold water. If it sinks and lies flat, it’s fresh. If it stands upright on the bottom, it’s older but usually still safe to eat soon. If it floats, discard it, as this often indicates spoilage. Floating happens because moisture and gases escape through the shell over time, creating a larger air pocket. You should also inspect the shell for cracks, slime, or unusual odors before boiling. During cooking, pay attention to the smell. Fresh eggs have only a mild scent. While overcooked eggs may release a light sulfur smell, a strong, rotten odor is a clear warning sign and the egg should not be consumed.

After boiling and peeling, rely on your senses again. Smell is the most dependable indicator—if the egg has a sour or unpleasant odor, throw it away immediately without tasting it. The egg white should be firm and slightly glossy, not watery or slimy. The yolk should be yellow and solid. A greenish-gray ring around the yolk can appear if the egg is overcooked, but this is harmless and safe to eat. Also consider storage time: hard-boiled eggs should be refrigerated and eaten within one week. If left out at room temperature for more than two hours, they should be discarded. When unsure about freshness, it’s always safer to throw the egg away rather than risk illness.