Food manufacturers guide to date labeling and lot codes

What are they for and why are they used?

For decorative purposes.
Photo by Agrifood Technology.

Processors can use the Michigan Department of Agriculture and Rural Development (MDARD) Food Labeling Guide to help them design a food label that meets the Michigan Food Law requirements.

This article focuses on two requirements within the labeling guideline: Sell-By Dates and Lot Codes.


MDARD’s Food Labeling Guide states: “All packaged, perishable foods (those with a shelf life of less than 90 days) must be labeled with a recommended last day of sale consisting of the month and day. Explanatory terms may also be used (such as sell by, sell before, last date of sale, or other meaningful terms).” In this case, MDARD is referring to a term for quality, not safety.

As the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) explains, “There are no uniform or universally accepted descriptions used on food labels for open dating in the US.” FSIS gives examples of commonly used phrases:

  • Sell By: Tells the store how long to display the product for sale for inventory management. It is not a safety date.
  • Best if Used By/Best Before: Indicates when a product will be of best flavor or quality.
  • Use-By: Is the last date recommended for use of the product while at peak quality.

Keep in mind that MDARD only allows a 7-day shelf life for refrigerated products unless a lab test proves it has a longer shelf life. When in doubt of whether you need a shelf-life test for your product, ask your MDARD Food Inspector.

Lot codes

The MDARD Food Labeling Guide states: “All prepackaged food must bear a meaningful lot code. This code must allow identification of a particular lot.” A sell-by date can be used as a lot code for products with a shelf life of less than 90 days.

What does this mean?

When manufacturers produce a product, they do so in batches. “Each batch that you produce is part of a single lot. Each product within the batch gets marked with a code that indicates which batch it came from,” explains BatchMaster Software, a leading manufacturing software company for the food industry.

Why are lot codes used?

If a processor is notified of a complaint, the lot code on the product can then be verified and cross-checked with the date it was produced and the batch it came from to identify the cause of defect. Lot coding also tracks which batches went to which customers or stores. This will be extremely helpful if you ever find yourself in the situation of wanting to recall your product voluntarily based on a quality issue or, in the worst situation, that an MDARD Food Safety Inspector orders you to recall your product based on a food safety issue.

Recipal, an online software for nutritional labeling and inventory management, explains, “To determine the lot code (aka batch code), you’ll use the Julian Calendar. It’s based on the day of the year the product is produced on.” For example, the year 2024 is a leap year with 366 days. To write January 5, 2024, as a Julian Calendar date, write 24 (the year) followed by 005 (the three-digit day of the year) to get the Julian Calendar number 24005.

Learn more about the labeling requirements for food processors by viewing the Michigan Department of Agriculture and Rural Development (MDARD) Food Labeling Guide.

The Michigan State University Extension Product Center can guide you further on this area. We have business counselors ready to assist you as you prepare for stores sales. Register today through the MSU Product Center website to become a client.

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