Bulletin E3258
Solving the Mystery of Food Product Dating


October 24, 2022 - <lmessing@msu.edu>

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Food product dating

When out grocery shopping, you’ve more than likely noticed numbers stamped on product packages. These numbers can cause confusion, and often deciphering them can be like solving a mystery. You will find calendar dates or “open dates” on perishable foods such as meat, poultry, eggs and dairy products. The consumer can easily read an open date. A “closed date” or “coded date” may appear on boxes and canned foods. Only manufacturers know the meaning of these dates. They probably confuse consumers the most.


Types of food product dating

The four types of dates include:
  • Sell-By: This date lets the storeowner or employee know how long to display the item for sale
  • Best if Used By: Consumers should use the product by this suggested date for best quality.
  • Use-By: This is the last date consumers should use the product for peak quality.
  • Closed or Coded Dates: These are packing numbers used by the manufacturer. 

What should I do if the date on the product expires?

Be sure to look at the “sell-by” and “use-by” dates on perishable foods. If the “sell-by” date has passed, don’t buy the product. The “use-by” date applies to the date you should use by at home.
It should be noted that dates found on products are the food manufacturer’s recommendations regarding optimal quality of the product. The dates are not necessarily guides for food safety. For instance, a product may be safe to eat beyond the “best if used by” date, but would not be of highest quality.
Also in most cases, the product date is determined for a product remaining unopened and stored in a proper manner. Once opened, the quality limits of the product will vary from the date printed on the package (Cornell, USDA, Food Marketing Institute, 2014, p. 4).

Can I use infant formula after the “use-by” date?

Do not buy or use baby formula after its “use-by” date. Formula must retain an adequate quality to pass through the nipple of the bottle. It can separate and clog the nipple if stored for too long. The Federal Drug Administration requires a “use-by” date on the product label. The manufacturer selects this date.

What do box and can codes mean?

A can must have a packing code to track the product. Manufacturers use these closed or coded dates to rotate stock and to track down the product in the event of a recall. These codes usually contain letters, numbers or both. Consumers should not try to interpret the codes. However, a can may also display a “best if used by” date for best quality. 

How long can I store cans?

You can safely store canned foods as long as you do not expose them to freezing temperatures or temperatures above 90 °F. High-acid canned foods such as tomatoes and fruit will keep their best quality for 12 to 18 months. Low-acid canned foods such as meats and vegetables will keep their quality for 2 to 5 years.

Egg carton dating

Federal law does not require the “sell-by” or “expiration” dates on egg cartons. Some states such as Michigan have egg laws that do allow the use of “sell-by” dates. Always purchase eggs before the “sell-by” or “expiration date” on the carton.
An egg carton with the USDA grade shield must display the “pack date” (the date that the eggs were washed, graded and placed in the carton). A “sellby” date on an egg carton bearing the USDA grade shield may not exceed 45 days from the pack date.
You can help keep eggs safe by making wise buying decisions at the grocery store. When purchasing and storing eggs, keep these points in mind:
  • Buy eggs only if sold from a refrigerator or refrigerated case.
  • Open the carton and make sure that the eggs are clean and the shells are not cracked.
  • Refrigerate promptly.
  • Do not store eggs in the refrigerator door, but in the main part, to ensure they maintain a consistent temperature.
  • Store eggs in their original carton and use them within 3 weeks for best quality


Cornell University, USDA Meat and Poultry Hotline, & Food Marketing Institute. (2014). The food keeper. (4th ed.). Retrieved from http://stlfoodbank.org/wp-content/uploads/2014/06/FoodExtensionList2015.pdf
USDA Food Safety and Inspection Service. (2013, August). Food product dating. (Rev. ed.). Washington, DC: Author.
Find out more about Michigan Food Safety at www.msue.msu.edu/safefood



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