Many shoppers notice mysterious numbers printed on egg cartons but are unsure what they mean. Besides the familiar date, cartons often include a three-digit code and a plant identification number. These markings are not random—they provide valuable information that can help you choose fresher eggs and understand where they came from.

One of the most useful markings is the Julian date, a three-digit code that shows when the eggs were packed. The system begins with **001 for January 1** and ends with **365 for December 31**. Comparing this number on different cartons can help you identify which eggs were packed most recently. You may also see a plant code, usually beginning with the letter **“P”** followed by numbers, which identifies the facility where the eggs were processed and inspected. This code is mainly used for product tracking and food safety.

Many cartons also display a **“sell by”** date, but this often causes confusion. It is intended to help stores manage inventory and does not necessarily mean the eggs are unsafe after that date. When refrigerated properly, eggs can often stay fresh beyond the printed date. Experts recommend storing eggs in their original carton to protect the shells, reduce moisture loss, and prevent them from absorbing odors from other foods. It’s also best to avoid washing eggs before storage because their natural protective coating helps keep contaminants out.

Before using eggs, you can check their freshness with a simple water test. Fresh eggs usually sink and lie flat, while older eggs may stand upright or float as air builds up inside the shell. Cracking an egg into a separate bowl is another good habit—a fresh egg has a firm yolk, thick white, and no unusual odor. Understanding these carton labels makes shopping easier and helps you choose the freshest eggs for better cooking results.
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