What the Numbers on Your Egg Carton Really Mean — And Why Ignoring Them Could Make You Sick

When you grab a carton of eggs from the refrigerator at the store, you probably check for cracks, maybe the expiration date — and that’s it. But printed on every egg carton are important numbers that many people completely ignore. Those numbers are not random. They tell you critical information about freshness, safety, and even where your eggs came from.

Understanding them could help you avoid food poisoning and make smarter choices for your health.

1. The Julian Date: The Real Freshness Code

One of the most important numbers on your egg carton is a three-digit code called the Julian date. It usually appears near the plant code and ranges from 001 to 365.

This number tells you the exact day of the year the eggs were packed.

For example:

• 001 = January 1

• 032 = February 1

• 365 = December 31

The lower the number, the earlier in the year the eggs were packed. Fresher eggs have a more recent packing date.

Even if the “sell-by” date hasn’t passed, eggs that were packed long ago may not be as fresh.

2. The Plant Code: Where Your Eggs Were Processed

You may also see a code that starts with “P” followed by several numbers (for example, P-1234). This is the processing plant number.

This code identifies the facility where the eggs were washed, graded, and packed. In case of contamination or a recall, this number helps authorities trace the source quickly and remove unsafe products from stores.

Ignoring this code during a recall could mean you unknowingly keep contaminated eggs at home.

3. Sell-By vs. Expiration Date

Many people assume the expiration date is the final safety deadline — but that’s not always true.

• Sell-by date: Tells stores how long to display the eggs for sale.

• Use-by date: Suggests when eggs are at peak quality.

In general, eggs can remain safe for 3–5 weeks after purchase if kept refrigerated at 4°C (40°F) or below.

However, eating eggs that are too old increases the risk of bacterial growth, especially Salmonella.