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Accurately Determining the “Best If Used By” Date

Best by date, food quality

It’s official! The USFDA issued a letter this month to announce that the voluntary, quality-based date labeling phrase should be standardized to “Best if used by” on packaged food products.

As indicated in the FDA letter, the “Best If Used By” introductory phrase communicates to consumers the date by which the product will be of optimal quality. So, the “Best if used by” date is about food quality, and not food safety, and recommends to consumers that products do not have to be discarded after the date if they are stored properly. This standardized date label would stop the confusion that has been around for many years where different phrases and statements have been used to describe the expiration date for food products.

As consumers, it’s everyone’s expectation to have quality foods. It’s also every consumer’s responsibility to minimize on food waste. The best practice for consumers is to buy the proper quantity of foods and make their own decisions about food quality and safety if used after the “Best if used by” date. While as food manufacturers, it’s important to set an accurate “Best is used by” date for each food.

So, how is “Best if used by” date determined?

Depending on the type of food, the way it is prepared, the packaging around it and the environment it is stored in, manufacturers decide the “Best if used by” date to guarantee the length of time that the food will maintain premium quality for consumption. Usually this is done through shelf life studies conducted by food scientists and taste panels. Please notice that this date only guarantees the quality of the food product before the package is opened and stored in proper environmental conditions.

How is food protected from spoilage?

There are different ways to protect food products from spoilage and quality degradation. To name a few, using good barrier packaging materials, modifying the ways of cooking, adding preservatives, storing the food in proper conditions, are among the methods to extend the shelf life.

In recent years, with the rise of consumer health awareness, minimum processing and clean labels (i.e. preservative-free) are more welcomed and are in ever increasing demand from consumers for today’s packaged foods. To use less preservatives but still extend the shelf life of foods, MAP (modified atmosphere packaging) processes have been widely used. For different types of food products, different ratios of gases, usually O2/CO2/ N2 are used to make up the gas mixture that the food product is stored in. MAP gas packaging extends the length of time food can be kept at its best quality.

As MAP processes are introduced into food packaging, it becomes more important for food manufacturers to select good gas barrier materials, as well as to study the integrity of the whole package in terms of leak-free package to ensure the MAP gas is maintained. A “Best if used by” date is only as good as the package’s ability to hold its MAP gas contents.

How do you know if your package is going to support your “Best if Used by” date?

1. Understand how much O2/H2O your barrier films are going to allow into the package

All polymer packages allow oxygen and water to permeate through the barrier materials. Food manufacturers need to understand how oxygen and water affect their product’s quality. Choose barriers with the right O2 and H2O permeability to protect your food’s quality for the duration you desire.

2. Check you package integrity

MAP packaged products will support your “Best if Used by” date if the package maintains its seals and integrity. If there is a significant leak in your package, there may be little to no MAP gas in your package shortly after your product is packaged, and as a result, you could experience a much shorter “Best if Used By” date than you desire.

To ensure your packaging has no leaks or integrity compromises, leak test your products. Use an instrument that can measure hole sizes down to at least 50 microns, because even at these small hole sizes, your MAP gas can be quickly exchanged with the ambient surroundings, and the protective benefits of your MAP can be rapidly diminished. To ensure your Best if Used By dates do not over-promise quality, check your package integrity often.

3. Check your MAP Gas Headspace concentration to ensure it is accurate

Modifying the atmosphere in your package to keep your food products lasting longer is only effective when the concentration of the gases in your package are at optimal levels. How do you know when your package is made, whether the MAP gases inside are correct? Use a Headspace MAP Gas Analyzer to determine the critical O2/CO2 concentrations in your MAP packages.

To food manufacturers, here are the takeaways:

  • Best if Used by date is a standard that will be used by US food companies going forward

  • To determine the “Best if Used by” date for your food products, consider conducting a shelf-life study on your packaged product. Many food manufacturers have turned to Modified Atmosphere Packaging (MAP) to create longer shelf-life food products without preservatives

  • MAP Packaging thus plays a critical role in the Best if Used By date, because if the MAP gas is either absent (e.g. due to leak or poor barrier/high-permeability) or inaccurate (i.e. wrong gas concentration), the food quality can deteriorate much faster than what is stated on a Best if Used By date



1. US FDA Letter, May 23, 2019 (

2. NPR News (


For more information on shelf life determination or testing please contact AMETEK MOCON at, visit or or call 763-493-6370.

Phillip Tan is the Director of Strategic Marketing at AMETEK MOCON in Mpls, MN. You can learn more about Phillip by visiting his Contributor Page.

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