How to tell if an egg is bad before you cook it

Check the shell first

Before cracking an egg, look for a clean, intact shell. Do not use a raw egg with a crack or leak: bacteria can enter through a damaged shell. If an egg cracked while it was hard-cooking, it may still be safe when thoroughly cooked, but a cracked raw egg from storage is best discarded.

Keep raw eggs in their original carton in a refrigerator at 40°F (4°C) or below. The carton protects the shells and makes it easier to keep track of the date.

Crack one egg into a separate bowl

If the shell looks sound and the egg has been stored properly, crack it into a clean bowl rather than directly into your recipe. Discard it if you notice a strong, sulfur-like or otherwise unpleasant odor, or an unusual appearance. Do not taste an egg to test it.

This is a useful spoilage check, not a guarantee of safety. Harmful bacteria can be present even when an egg looks and smells normal. Cook eggs thoroughly and follow storage guidance every time.

Do not use the float test as a safety test

An egg that floats in water has a larger air cell, which often means it is older. It does not prove that the egg is spoiled or unsafe. A sinking egg is not automatically safe either. Use the float test only as a quality clue, then consider storage history and inspect the egg in a separate bowl before cooking.

Use time and temperature as your safety check

For best quality, the FDA advises keeping shell eggs refrigerated and using them within three weeks. USDA storage guidance lists raw shell eggs for three to five weeks in the refrigerator. Treat those as storage windows, not a replacement for sensible handling.

Hard-boiled eggs should be refrigerated within two hours of cooking and used within one week. If eggs have been left at room temperature for more than two hours, discard them. When in doubt about an egg’s storage history, the safest choice is to throw it away.