How do I read the expiration date, or code dating, on a label?
First, it is important to decide what type of code date is on the package as each manufacturer may use a date that means something different.
For example, some products are coded with a "use by" date which means the product's quality and safety can only be guaranteed until this date. Other manufacturers have a "sell by" date indicating that after this date, stores should not sell the product. Still other products have a "best by" date which means the product's quality can only be assured until this date. And there are also products that use a "made on" date, or a date that indicates when the product was produced.
Once you know what type of date is on the package (use by or sell by, etc.), the next step is to identify what the code date means. Many code dates are based on a Julian calendar.
This means that January 1st equals "1" and the last day of the year, Dec 31, is "365." The year can be represented a variety of ways depending on how the manufacturer chooses to list it.
There may also be parts of the code the manufacturer uses to track products. For instance, extra letters and numbers may be included in the code to represent the specific location, plant, or month the product was made in.
There are many possible code date combinations and systems so if you are unsure how long a product should be kept, it is always best to contact the manufacturer. They will be able to tell you how the code date should be read. Also, manufacturers can provide information regarding how long the product should be kept.
A quick reference to understand the different types of code dates can be found at: http://www.fsis.usda.gov/Fact_Sheets/Food_Product_Dating/index.asp .
Answered by Jessica Kovarik, RD, LD, Extension Associate, College of Human Environmental Sciences, University of Missouri Extension