Many of us check the expiration date before we buy perishable goods—eggs included—but there's another subtle code on your egg carton that often goes unnoticed. Next to the expiration date is a three-digit code, which actually represents a date in Julian calendar format. This represents the day your eggs were packed. So, for example, if the three digits are 274, then your pack date was the 274th day of the year—or October 1. According to , fresh eggs can be kept in the refrigerator up to four to five weeks past the pack date.
The USDA also provides a to help you quickly convert the Julian calendar code to a month and day. Remember that the numbers will vary slightly on a leap year (but you won't need to worry about that until 2020).
Besides the pack date, there's even more to your egg carton than you may have realized. All USDA-graded egg cartons must include a processing plant code and a grade indicating egg quality.
By looking at the processing plant code, you can see where your eggs were packaged and how local they are. The plant code usually starts with a P, followed by a four digit number. If you're feeling curious about where your eggs come from, you can use this from the USDA to look up the plant's location.
The most recognizable feature on an egg carton is the grade, which ranges from AA to B. It's just like school: Grade AA is equivalent to earning an A+. These are the freshest eggs and the highest quality. Grade A eggs are just a notch below these and are still highly praised. And grade B eggs aren't necessarily bad; they're just not meant for your ham and cheese omelette. Instead, they're often used for baking and to create various egg products, like the egg in a frozen breakfast sandwich.
So next time you're in the dairy aisle, take a closer look at your egg carton—you'll be surprised what all you can learn.
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