The Date on Your Egg Carton May Not Mean What You Think
You open the refrigerator, reach for a carton of eggs, and notice a string of numbers printed along the side. One might say “Best By,” another may begin with the letter “P,” and somewhere nearby you may spot a mysterious three-digit number.
If those codes have ever left you wondering whether your eggs are still safe to eat, you’re not alone.
The good news is that these markings don’t all mean the same thing. In the United States, that three-digit number may actually be a pack date—a code that indicates the day of the year the eggs were processed and placed into the carton.
Understanding these small numbers can make it much easier to manage the eggs in your refrigerator and decide which carton to use first.
What Does the Three-Digit Number on Eggs Mean?
The three-digit code represents the day of the year, using numbers from 001 through 365.
For example:
- 001 = January 1
- 032 = February 1
- 198 = July 17 in a non-leap year
This code is different from an expiration or quality date. Instead, it gives you information about when the eggs were packed.
If you have two cartons of eggs in your refrigerator, the pack date can help you determine which one is older and should be used first.
What Does the “P” Code Mean?
You may also notice a code beginning with the letter “P.”
This generally identifies the processing or grading plant where the eggs were handled. While this information may not be particularly useful during an everyday grocery trip, it can help trace eggs through the food-supply system if a food-safety issue or recall occurs.
You may also see terms such as “Sell By,” “Best By,” or “Best Before.”
These dates can serve different purposes. A sell-by date primarily helps retailers manage inventory, while a best-by date is generally associated with expected quality.
That means reaching a printed date does not necessarily mean an egg instantly becomes unsafe.
How Long Do Eggs Last in the Refrigerator?
According to USDA guidance, raw shell eggs generally keep for around three to five weeks when properly refrigerated at 40°F (4°C) or below.
For the best storage conditions, keep eggs in their original carton and place them on an interior refrigerator shelf rather than in the door. The carton helps protect the shells, while the interior of the refrigerator tends to have more stable temperatures.
Remember, however, that freshness and food safety are not exactly the same thing.
An older egg may still be usable, while a fresh-looking egg can potentially contain harmful bacteria.
Can the Water-Float Test Tell You If an Egg Is Safe?
You’ve probably heard of the popular water test: place an egg in a glass of water and see whether it sinks or floats.
While this can provide a rough indication of an egg’s age, it cannot tell you whether the egg is contaminated with bacteria such as Salmonella.
As an egg ages, its air cell gradually becomes larger, which can cause it to float. But an egg that sinks isn’t automatically free of harmful bacteria, just as a floating egg isn’t necessarily dangerous.
When it comes to food safety, appearance and simple freshness tests aren’t enough.
