Egg cartons can be confusing because they often display several dates and numbers. The three-digit code found on many U.S. cartons is usually a pack date, not an expiration date. It indicates the day of the year when the eggs were processed and packaged. The code ranges from 001 to 365, with 001 representing January 1. For example, 032 means February 1, while 198 means July 17 in a non-leap year. This information can help you compare cartons and use older eggs first, but it does not determine whether an egg is safe to eat.
You may also notice a code beginning with “P.”, which identifies the processing or grading facility. Other labels, such as “Sell By,” “Best By,” and “Best Before,” serve different purposes. A sell-by date mainly helps stores manage inventory, while best-by dates generally relate to quality. Proper refrigeration is essential for freshness and safety. USDA guidance states that raw shell eggs generally keep for about three to five weeks when refrigerated at 40°F (4°C) or below, preferably on an interior refrigerator shelf in their original carton.
Freshness and safety are not the same. An egg may look and smell normal while still carrying harmful bacteria such as Salmonella. That is why the popular water float test cannot prove whether an egg is safe. Floating usually means the egg has developed a larger air cell as it ages. For safer handling, keep eggs refrigerated and avoid using cracked or heavily contaminated shells. Wash your hands, utensils, and surfaces after handling raw eggs to reduce cross-contamination.
When cooking eggs, FDA guidance recommends cooking them until the whites and yolks are firm. Cooked egg dishes generally last three to four days in the refrigerator, while hard-cooked eggs can keep for about one week. The main lesson is simple: use carton codes as helpful information, but do not rely on them alone. Keep eggs cold, protect the shells, prevent cross-contamination, cook them properly, and refrigerate leftovers promptly. If an egg has been badly cracked, contaminated, or stored at unsafe temperatures for too long, it is safest to discard it.