That is why the popular water float test should not be treated as a safety test. An egg floats when its internal air cell becomes larger as the egg ages, but floating does not prove that harmful bacteria are present or absent. Instead of relying on the float test, pay attention to proper storage and handling. Eggs with cracked or heavily contaminated shells should generally be discarded, because damaged shells can provide bacteria with an easier path inside.

Safe preparation is also important. Always wash your hands, utensils, and countertops after handling raw eggs to prevent cross-contamination with other foods. When cooking eggs, FDA guidance recommends cooking them until both the whites and yolks are firm. This is especially important when serving eggs to people who may be more vulnerable to foodborne illness.

Once eggs are cooked, they should be refrigerated promptly. Cooked egg dishes generally remain good for about three to four days in the refrigerator, while hard-cooked eggs can usually be kept for about one week. Keeping them properly chilled helps maintain both quality and safety.

Ultimately, the numbers printed on an egg carton are useful clues, not guarantees. The pack date can help you understand how old the eggs are, while sell-by and best-by dates provide additional information about retail handling and quality. But the safest approach is simple: keep eggs cold, protect their shells, prevent cross-contamination, cook them thoroughly, and refrigerate leftovers promptly. If an egg has been badly cracked, heavily contaminated, or left at unsafe temperatures for too long, throwing it away is the safest choice.