Egg cartons can contain several dates and codes, but they don’t all mean the same thing. A sell-by date mainly helps stores manage inventory and does not automatically mean eggs become unsafe that day. Similarly, “Best By” or “Best Before” dates generally relate to quality. A three-digit number, however, usually represents the packing date, shown as the day of the year, while a code beginning with “P” identifies the processing or packing plant. These markings can also help trace eggs during food-safety recalls.

Freshness and safety are not exactly the same. Properly refrigerated eggs can generally remain usable beyond a sell-by date, but eggs can still carry Salmonella even when they look completely normal. The FDA recommends keeping eggs refrigerated at 40°F (4°C) or below, storing them in their original carton and avoiding the refrigerator door, where temperatures fluctuate more. USDA says shell eggs can generally be refrigerated for three to five weeks, assuming proper handling and storage.

If the carton date has passed, don’t automatically assume the eggs are unsafe. Consider whether they have been continuously refrigerated, whether the shells are cracked or damaged, and whether there are obvious signs of spoilage. However, eggs exposed to unsafe temperatures or questionable handling should be discarded. When cooking, the FDA recommends preparing eggs until the yolk and white are firm, while egg dishes should reach 160°F (71°C). Pasteurized eggs can be a safer choice for recipes containing raw or undercooked eggs.

So, the next time you see a mysterious number on your egg carton, remember: the three-digit number is generally the pack date, “Sell By” relates to retail timing, “Best By” indicates quality, and “P-####” identifies the plant. Understanding these codes can help you judge freshness more confidently, but safe refrigeration, handling, and thorough cooking remain the most important factors.