Consumption Factors

The StepLadder Series is a Steptoe publication focused on discussing food contact regulatory topics in plain language.

Author's Note:

FDA has stated publicly that it is in the process of updating its list of consumption factors and expects to announce updated values in the coming months. Continue to stay tuned!

There’s more than one way to slice a pie.

The Relationship Between Migration and Dietary Concentration

In our last StepLadder article, we discussed the "No Migration" position – effectively, a threshold by which one can make a self-determination that a substance does not migrate to food from food packaging at a specific limit of detection (LOD), such that it would not be considered a "food additive," as that term is defined by the Federal Food, Drug, and Cosmetic Act. The use of a migration value is one method by which a company could establish that a food-contact substance, or component thereof, is subject to an exception from the need for premarket approval by the US Food and Drug Administration (FDA).

The principle of dietary concentration takes this discussion one step further, and is one of the defining ways in which FDA regulates food-contact substances differently than its counterparts in other jurisdictions, such as the European Union (EU).¹  The basic premise is this:

Migration <M> × Consumption Factor (CF) = Dietary Concentration (DC)

Consumption factors are values that represent "the fraction of the daily diet expected to contact specific packaging materials. The CF represents the ratio of the weight of all food contacting a specific packaging material to the weight of all food packaged."² Through the use of consumption factors, one is able to assess the upper-bound potential exposure to a food-contact substance in the diet, based on the calculated, estimated, or measured migration of the substance from packaging to food. If migration is the pie, dietary concentration is the slice of the pie.

Consumption Factors

FDA's consumption factors for various types of food packaging appear in its Chemistry Guidance document.³  They are repeated for ready-reference immediately below:

Courtesy US Food and Drug Administration – website last visited August 5, 2023

As we explore consumption factors further, we note that FDA divides the 'universe' of food packaging into two types: (1) general; and (2) polymer. The "general" category includes non-polymeric substrates (that, despite the "general" category name, includes substrates with polymeric coatings), such as: uncoated, clay-coated, and polymer-coated paper, polymer-coated and uncoated metal, adhesives, retort pouches, microwave susceptors, and glass. The "polymer" category – perhaps referred to more accurately as the "polymeric substrate" category – includes food packaging composed of polyolefins (high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polypropylene (PP)), polystyrene, polyvinyl chloride (PVC), polyethylene terephthalate (PET), nylon and acrylics, among others.

Utilizing these consumption factors, one can compare the resulting dietary concentration value to relevant oral toxicology studies and their safety benchmarks to establish the safety of the substance when exposure occurs through the oral route of exposure. Here's a (fictional) example of how consumption factors may be used:

• An antioxidant is added to HDPE at a level of 0.025%;
• Based on additional factors (described in our "No Migration" StepLadder article), we determine through calculation that the upper-bound potential level of migration <M> of the antioxidant to food would not exceed 30 parts per billion (ppb);
• We then multiply the <M> value by the relevant CF for HDPE – 0.13 (13%) in this case – to calculate an upper-bound potential concentration of the antioxidant in the diet (the dietary concentration) of 30 ppb × 0.13 = 3.9 ppb.

Depending on the toxicology profile of the substance, one could then consider the use of the migration value (<M> = 30 ppb) to establish a "No Migration" position or alternatively, the dietary concentration (DC = 3.9 ppb) to reach a Generally Recognized as Safe (GRAS) determination,⁴ as appropriate exemptions and exceptions to the need for premarket approval under the Act, respectively.⁵For various reasons, it may be advantageous for a company to utilize one approach over another, when both are otherwise available. In other instances (e.g., when a migration value is too high to reach a "No Migration" determination, often because the substance is or would be detected at the limit of analytical sensitivity), the use of consumption factors provides an alternative method for establishing an FDA status for the food-contact substance on the basis that the dietary concentration is sufficiently low such that premarket approval by FDA is not required.⁶

The "Default" Consumption Factor

As seen in the table above, FDA provides a consumption factor of 0.05 (or that 5% of the daily diet will contact packaging) for "all other" packaging categories not specifically defined. This category is sometimes used for specialty chemistries or novel polymeric substances where FDA has not yet publicly established a consumption factor value. The default consumption factor may also be utilized on a case-by-case basis where the consumption factor for the general category of packaging material is inappropriate to use based on unique aspects of the packaging or its marketing profile – such as where the packaging that is expected to contact a much smaller fraction of the diet than the otherwise appropriate value, such as in specialty applications. 

For obvious reasons, the use of the default consumption factor – particularly in lieu of those consumption factors that are applicable to the general category – should be fully supported when relied upon to convert a migration value to a dietary concentration value. When a company later learns or expects that the specific circumstances governing the use of the default consumption factor change (such as when FDA establishes a consumption factor for a type of packaging where one previously did not exist; or where the unique aspects of the packaging are more commonplace), the dietary concentration analysis should be revisited accordingly.

"Build Your Own" Consumption Factor

In certain situations (and always on a case-by-case basis), a manufacturer of a novel food packaging material may have data or information demonstrating that the market penetration of the material is exceedingly low – and by definition, less than 5% – such that it may be more appropriate to independently develop a consumption factor for purposes of establishing a suitable FDA status for the food-contact material, as opposed to using the default value. As an example, companies can rely on published (or unpublished) sales and market data to support the use of a smaller value, provided again that this value is appropriately updated as market conditions change.

Relatedly, companies may rely on data and information (usually confidential to the company or relevant trade association(s)) to support a revised consumption factor (CF') smaller than FDA's values for a known packaging type by utilizing a market volume limitation (MVL). The use of an MVL is appropriate only in the specific circumstance where the company has detailed information about its current and expected production of a food-contact substance (usually by poundage), relative to the total poundage of material that it would likely replace or substitute, where CF × MVL = CF'. The use of an MVL is usually time-limited, as changes to production values will necessarily increase or decrease the CF over time. While FDA has historically accepted the use of market volume limitations in the context of Food Contact Notification (FCN) submissions, the Agency has applied heightened scrutiny to this practice in more recent years.

Updated Consumption Factors are on the Horizon

During Steptoe's Earth Day 2023 Food Packaging Conference at our Washington, D.C. office in April 2023, representatives from FDA discussed the Agency's efforts to comprehensively update its table of consumption factors for the first time since 2007.⁷ As part of this project, and during her previous time at FDA, Steptoe's own Dr. Jessica Cooper supported the Agency by collecting and evaluating new and updated market penetration information for various types of food-contact materials and articles, including both currently-listed and more recent chemistries. 

While the updated consumption factors have not yet been finalized by FDA, and remain subject to change, the Agency provided an overview of potential changes in a June 2022 presentation to the Plastics Industry Association (PLASTICS) in Baltimore, Maryland.  Based on this presentation, we understand generally that:

• The CF for PET is expected to significantly increase, reflective of a substantial increase in the use of the polymer to hold food in the US over the past decade;
• The CF for paper and paperboard is expected to decrease;
• The CF for polystyrene is expected to significantly decrease; and
• The total CF for all polyolefins (as a category) will remain largely unchanged, though certain CF values for specific polyolefin polymers will see increases or decreases.

It remains to be seen to what extent FDA and industry will each leverage updated consumption factors to evaluate the use of food-contact materials moving forward, as well as addressing previous authorizations for food-contact substances where new and expanded clearances are sought. One thing is for certain, however – FDA's forthcoming consumption factor update will have a significant impact on safety assessments for food packaging moving forward, so continue to stay tuned!

¹ The European Union (EU) relies most commonly on the measure of migration of a substance from food packaging to food as a method of regulating the suitability of food packaging.

² FDA Guidance for Industry: Preparation of Premarket Submissions for Food Contact Substances (Chemistry Recommendations), December 2007, accessible at: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/guidance-industry-preparation-premarket-submissions-food-contact-substances-chemistry

³ Id. at Section II.E ("Consumer Exposure"), paragraph 1 ("Calculation of Exposure"), subparagraph a ("Consumption Factor"). 

⁴ GRAS determinations are a complex topic that will be discussed in future StepLadder articles - stay tuned!  For purposes of this discussion, simply note that GRAS substances are specifically exempted from the need for premarket approval under the Act.

⁵ One could similarly use consumption factors as a method of demonstrating that the presence of a residual impurity or byproduct is safe, and does not impact the suitable purity of the finished food-contact material or article.

⁶For intentionally added food-contact substances, low dietary concentration value alone is not sufficient to establish a suitable FDA status.  One also must rely upon well-established scientific and legal principles to demonstrate that this low level of exposure is generally recognized as safe.

⁷ We understand through various correspondence and Freedom of Information Act (FOIA) submissions with and to FDA, respectively, that the Agency has updated certain consumption factors on a case-by-case basis in the interim. These updates have occurred most often as a result of new information provided to the Agency by a notifier in the context of an FCN submission. 

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About the Steptoe StepLadder Series

Steptoe & Johnson LLP is pleased to publish the Stepladder series of articles for our clients, prospective clients, and interested companies as a way of educating attorneys and non-attorneys alike about legal and regulatory principles related to food packaging in meaningful ways. While there are many sources of information available online, the StepLadder series is intended to be accessible to, and understandable by all, to help support business decisions related to food packaging compliance.

This information is provided for educational purposes only, is not legal advice, and does not establish an attorney-client relationship with Steptoe. Our lawyers made us write that.  If you have legal questions, please consult an attorney. Preferably from a team well-versed in food packaging regulation – and definitely from a group of attorneys that have a good sense of humor. Because you are what you eat… unless your food packaging isn't a 'food additive,' in which case you’re not food packaging.