The food packaging industry is working hard to safeguard food packaging and our food supply. Promising practices are underway to tackle PFAS in food packaging. This article summarizes much of the activity. First, the conundrum of distinguishing between Intentionally Added Substances (IAS) and Non-Intentionally Added Substances (NIAS) is being abandoned. This origin-agnostic approach is inevitable because it links the requirement for a safe environment to grow food to the need for safe food-contact packaging as well as, pragmatically, the need for clear packaging industry direction on the allowable levels of PFAS. Packaging suppliers, brands, retailers, and post-consumer package waste handlers are also focused on adding value by mitigating PFAS in packaging. This is shaping the industry to be more transparent and aligning with the need for enhanced track-and-trace in our food industry. Third, alternate packaging materials and coatings for grease/oil resistance are gaining prominence, prompting PFAS replacements to enter the food packaging industry ahead of schedule.
Abandoning the Conundrum of NIAS vs. IAS
Origin-agnostic legislation is moving forward. Global governing bodies regulating chemical presence in food distinguish between IAS and NIAS less frequently.
The distinction between IAS and NIAS has not been made in many regulations, either historically or explicitly in recent years. The initial lack of attention to the IAS and NIAS distinction originated in municipal and military water regulations and then in packaging for military rations. The EU Regulation No. 2019/2021, enacted in the summer of 2019, pertains to the regulation of persistent organic pollutants (POP) per the Stockholm Convention and does not distinguish between IAS and NIAS. South America mirrors the EU in migration limits. The U.S. military instituted the phase-out of PFAS within firefighting foam and prohibited the use of PFAS in Meals Ready to Eat (MREs) packaging in 2020.1 Likewise, six PFAS have legally enforceable levels for municipal water supplies, and the distinction between IAS and NIAS has not been made.
Furthermore, the U.S. Environmental Protection Agency (EPA) prohibits the manufacture, processing, or use of an estimated 300 "inactive PFAS" (PFAS that have not been manufactured or used for many years) without a thorough EPA review and risk determination. In this prohibition, the EPA does not distinguish between IAS and NIAS. EPA set the perfluorooctanoic acid (PFOA) health advisory in water at 0.004 parts per billion (ppb).
Likewise, there is a trend toward legislating PFAS levels in packaging regardless of IAS or NIAS origin, efficacy, or economic value. The original model legislation derived from the Toxics in Packaging Clearinghouse created in 1992 by the Coalition of Northeastern Governors (CONEG) focuses solely on the presence of chemicals. Legislation adopted in 19 states was designed to ban the use of four heavy metals. This ban has now been expanded to include PFAS with variable restrictions and threshold levels. Critically, regulations need to address the food safety of packaging in direct contact with food and ensure the disposal of packaging in the environment.2 Furthermore, California, which often dictates U.S. packaging legislation due to its economic size, prohibits the distribution, sale, or offer for sale of only PFAS above 100 ppt in only plant fiber-based packaging containing PFAS, regardless if PFAS is intentionally or non-intentionally added. At press time, 35 U.S. states had enacted PFAS-related legislation.
Epidemiological and toxicological studies indicate that exposure to PFAS can cause cancer, reproductive, developmental, cardiovascular, liver, kidney, and immune system issues. Furthermore, PFAS toxicological impact does not depend on whether a compound has IAS or NIAS origins, and toxicity has been established.3,4 It has been established that PFAS can migrate into foods and that migration of PFAS, as with other substances, is a function of the food properties (fat, pH, alcohol level, etc.) and chemical idiosyncrasies (crystallinity, orientation, degree of polymerization) of the packaging material and conditions (temperature, relative humidity, and time) of contact.5
PFAS levels of zero may not be consistently achievable, given increased detection from parts per thousand to parts per trillion (ppt) and the existence of PFAS in our environment. Restricted substance lists (RSLs) are in effect, akin to the U.S. Food and Drug Administration (FDA) regulations on these substances without threshold values or the EC 10/2011 regulation with a lower than 10 ug/kg limit. For example, countries such as Denmark, as well as the U.S. state of Rhode Island and the city of San Francisco, California, have banned PFAS at any level. Rhode Island House bill H7438/Senate bill S2044 explicitly states, "The use of a regulated chemical as a processing agent, mold release agent, or intermediate is considered intentional introduction for this chapter where the regulated chemical is detected in the final package or packaging component." Similarly, Maryland House Bill 275 prohibits the production, sale, and distribution of PFAS that were knowingly added to materials designed and intended for direct food contact.
Although the IAS and NIAS distinction is clumsily extended to packaging in some legislation, the trend is to focus on the amount of PFAS. The historical differentiation between IAS and NIAS, the subsequent confusion it has caused, as well as the identical toxicological effects of IAS and NIAS justify this origin-agnostic prevailing legislation.
Naïve origin of NIAS
Packaging is an indirect food additive. All packaging components in direct food contact (without a functional barrier between food and package material) are included as indirect food additives. Importantly, this applies to plastic, metal, paperboard, wood, glass, and any composite packaging material, as well as to inks , adhesives, and release agents used in converting these materials into their final package format. FDA and similar global governing bodies measure and authorize PFAS and other chemicals of concern in food packaging.6,7 NIAS are chemicals present in packaging but not introduced intentionally. They are the result of the generation and conversion of raw materials used in packaging, as well as in the production and filling of packaging. In Europe, the term NIAS was introduced in a legal context specifically for plastics in Commission Regulation (EU) No. 10/2011, sections 18 and 20.
Confusion Between IAS and NIAS
The confusing scope of NIAS is best explained by the Johari Window concept since there are known and unknown sources, as well as known and unknown compounds.8 Moreover, the packaging has different definitions of what constitutes an NIAS. For example, since PFAS are known to exist within recycled polymers,9 the presence of PFAS within packaging made from recycled polymers can be considered IAS since recycled polymers were intentionally used. Importantly, FDA regulations permit only the use of recycled polypropylene and polyethylene food contact polymers that have previously been used in contact with food.10 Thus, if a tight chain of custody is not observed and documented, NIAS can become IAS. Likewise, recycled paperboard can be construed to contain PFAS as an IAS if it was made from recycled paperboard that was coated with grease-resistant PFAS. The continued use of recycled packaging materials made before regulations that restrict or ban phthalates, bisphenols, and perfluorinated compounds for adhesives, inks, phthalates, photo initiators, oligomers, and additives can increase the risk of using recycled paperboard and polymers for food contact packaging.11
Furthermore, package recycling can produce new compounds from IAS chemicals. Most reactions and their secondary and primary reaction byproducts are known, although some are not known. Therefore, producing new compounds can be considered either IAS or NIAS.
The distinction between IAS and NIAS based on the functionality of additives has also been substantively made.12 In this research, levels of PFAS well below the efficacy level of providing grease/oil resistance were considered as NIAS since they did not have a grease/oil resistance functional purpose and, therefore, would not be added because there was no economic or rational reason to add PFAS. The different efficacies of these types of PFAS were addressed by considering only levels well below any efficacy. This is practical and economically defensible only when the specific purpose of a substance is known, such as grease-resistant PFAS coatings on paperboard; and when contaminated (in this example case, by PFAS), recycled paperboard is not lower cost.
In general, PFAS is considered an IAS when it is used in food packaging when it performs the following functions:
- Acts as a release agent: This is used in thermos-, injection-, and blow-molding operations to reduce adhesion between the mold and polymers.
- Serves as an emulsifying, foaming, and dispersing agent: Emulsifiers assist in producing polymers. PFASs bond with functional groups such as acids and alcohols and/or can participate in condensation polymerization of nylon and polyethylene terephthalate (PET).
- Improves barrier: Fluorination of polyethylene (PE) was approved in 1983. High-density polyethylene (HDPE), polypropylene (PP), and PET are fluorinated with hexaﬂuoropropylene (HFP), tetraﬂuoroethylene (TFE), and vinylidene ﬂuoride (VDF) to improve barrier properties enabling the use of thinner or lower-cost polymers. For example, fluorination of HDPE during blow-molding operations improves barrier properties, so a thinner HDPE bottle is needed to protect the product. This improves sustainability and lowers bottle cost since less plastic is needed per bottle.
- Improves grease and oil resistance: For many foods, grease and oil barriers are essential for preserving flavors, texture, and mouthfeel while safeguarding consumers from grease and oil. Products like cooked or fried meats, fish, poultry, fried potatoes, chips, cookies, crackers, salad dressing, and some fried foods must be packaged in grease- and oil-resistant materials. Paperboard, corrugated paper, and hygroscopic polymers like polyactic acid (PLA), cellulose, starch, and ethylene employ PFAS to obtain resistance to grease/oil.
The presence of PFAS is often considered as NIAS if PFAS is derived from:
- Contamination of food and packaging production environments: Knowledge of chemical processes, manufacturer experience, and utilization conditions can be used to predict and limit PFAS as an NIAS. These substances are identified and quantified with relative ease using targeted chemical analyses and sources eliminated. Significantly, abrasion of production equipment increases surface area and sites for subsequent migration. Coatings on cartoners, labelers, conveyors, thermoformers, unnesters, and unscramblers inhibit sticking and make production lines move smoother/faster. Prior to packaging, food extruders, ingredient conveyance systems, hoppers, and mixers can transfer PFAS into food. Water and clean-in-place (CIP) cleaning agents can move PFAS within the production environment. As noted earlier, in some instances when contaminants are known, they can also be considered IAS.
- Reaction byproducts: Typical examples of reactions include polymerization byproducts derived from the production of can coatings, as well as antioxidants and UV stabilizers that have harmful degradation products. For example, the vinyl chloride monomer within polyvinylchloride (PVC) was once considered an NIAS because of an incomplete polymerization process. Sources of contaminants can be diverse because impurities and environmental exposure vary. As noted earlier, in some instances, these reaction byproducts can be considered IAS.
Promising PFAS Alternatives and Solutions
Regardless of the IAS and NIAS distinction, the packaging industry has responded admirably and implemented packaging without PFAS well ahead of initial targets. Research on alternatives to PFAS as a grease/oil packaging barrier is rapidly progressing. Relevantly, a grease-/oil-resistant barrier needs to be:
- Effective at the temperature, humidity, and times of use
- Economically feasible
- Aligned with existing package production and distribution processes
- Have a consistent, reliable source
- Researched so it does not contain a regrettable substitute
- Recyclable when on a packaging substrate
- Compatible with needed ink and adhesives.
When grease and oil barriers are more efficient, less packaging material is required to achieve the same barrier properties. Producing, processing, and disposing of packaging with less material reduces the cost and environmental impact. Packaging substrates—paperboard and plastics—require grease/oil barriers, and the foods that require these barriers are essential to consider when developing alternatives.
Material science and coating chemistry govern the strategies used to improve grease and oil resistance in packaging. Grease resistance is typically measured using a contact angle measurement in a modified ASTM D7334-08 process. Notably, measurements are specific due to the unique nature of how grease/oil is bound within the food matrix, the different packaging substrate surface areas, as well as varied conditions of use. For example, a grease barrier for McDonald's French Fries hot from the fryer into a paperboard sleeve differs from Hormel Bacon and Kettle Potato Chips (precooked) due to differences in condition of use.
Switching Barriers, Altering Structures, and Coating Chemistry are Promising
Switching materials. Switching to a material with better inherent grease/oil resistance is a viable option for achieving greater grease/oil resistance. Surface hydroxyl groups on paperboard fibers "soak" in grease and oil upon direct contact, and grease and oil soften/plasticize the ordinary polyolefins of polyethylene, polypropylene, and polystyrene, which can lead to delamination or packaging integrity loss. It is possible to transition from a polyolefin to metal, glass, or PET, a polymer with better chemical resistance.
Altering paperboard structure. Altering paperboard structure itself holds promise because if the grease and oil resistance is inherent, even if the paperboard surface is penetrated, it retains a high grease resistance. Besides controlling the length and refinement of paper fibers, increasing the density of paperboard and strengthening the internal bonds are other methods to provide inherent resistance to grease and oil. The higher price of higher-density paperboard is due to its increased fiber content. However, since tensile and burst strength is enhanced, using a thinner, less expensive paperboard is often possible.
Other means of improving inherent grease and oil resistance are the use of strong acids to break existing bonds between the cellulose paper fibers. This produces a cellulose gel that, when dried, forms an oil-resistant barrier. Additionally, wetting agents and chemical compounds that form bonds with the hydroxyl groups of cellulose can be used to modify wet fibers. The extensive drying time required to produce this inherently grease- and oil-resistant paperboard increases preparation time and energy costs.
Creating alternative coatings. Rethinking coatings has resulted in breakthroughs. Oil-/grease-resistant filler options include:
- Dispersions and clays
- Carboxymethyl and hydroxyethyl celluloses
- Talc-polyacrylate blends
- Wheat proteins.
In addition, grease/oil coatings with varying degrees of resistance include:
- Polybutylene adipate terephthalate
- Polybutylene succinate
- Alkyl ketone dimer
Fillers and coatings options work in unison. For example, the common use of calcium carbonate as a filler content necessitates alkaline pH coatings. However, if this filler is replaced with one that aligns with acidic pH coatings, then more viable oil-/grease-resistant coating options exist.
Although PFAS have been approved for wet pulp use, PFAS are more effectively applied during the drying end of paperboard production. Notably, before coating and calendaring processes that eliminate air pockets within and on the paperboard matrix, paperboard consists of about 50 percent air. Since the inherent air pockets of paperboard are filled during the drying process to facilitate even distribution of color, adhesives, and other coatings, it is often more cost-effective to apply grease and oil resistance additives during the dry end rather than during the wet pulp stage of paper production.
PFAS alternative oil-/grease-resistant coatings can insightfully crack and "flake off" into the food. Innovation in blending many of these alternative coatings helps achieve a balance of barrier properties, flexibility to provide a sufficient barrier, and flexibility. For example, there are concerns such as sourcing with chitosan and recycling with wax and cracking, which can puncture the coating. Thus, lower grease resistance is a common issue with PFAS substitutes. Improved bonding of coatings to cellulose can reduce coating cracking. For example, functional groups such as alkenyl succinic anhydride form ester bonds with the hydroxyl groups of cellulose. Shifting from existing paperboard production and distribution and reconsidering the coating application's time and place provide more options. For example, coating cracking is common prior to food being placed in contact with the packaging due to long-term storage, high temperatures, and cutting and scoring operations after the paperboard is coated with oil-/grease-resistant coatings. Applying coatings after paperboard containers have been assembled and just prior to filling with food avoids this distribution-related cracking. In the quick service industry, for example, paper sleeves can be opened and sprayed with coatings just before fries are added, allowing the coatings to fill gaps and creases without being damaged during shipping and handling if coating is applied at the paperboard converter.
Importantly, solutions for grease- and oil-resistant food packaging should not be regrettable substitutes. They should be consistent with current toxicity knowledge and projected restrictions on the use of additives in food packaging. This presents a promising prospect for advancing and aligning food packaging research conducted at institutes and universities, focusing on industry-oriented outcomes. To ensure the protection of consumers on a global scale, it is imperative that the elimination of chemicals from a specific region, based on robust scientific evidence, is accompanied by the removal of these chemicals from packaging materials in other countries, as well. This is because removing hazardous chemicals, such as PFAS, enables the safe and economical global reuse of recovered, recycled, or repurposed packaging.
Stronger Value Chain-Derived Shared Value
The packaging industry serves the food industry in protecting and promoting food. The entire food packaging value chain is actively engaged in achieving levels of PFAS that are below toxicological impact.
Packaging with the lowest level of PFAS and other chemicals of concern—essentially "clean packaging"—presents a potential avenue for restoring confidence in packaging. This can be achieved by applying the expertise of existing organizations to establish and harmonize regulations to ensure that food packaging materials are safe for consumers; that they are recyclable, compostable, and reusable; and that packaging does not represent a barrier to trade. Removing chemicals of concern from packaging and packaged goods across all international operations and sales facilitates unobstructed trade.
Linking PFAS to More Sustainable Packaging
Brands are expanding sustainability strategies to include clean packaging with the lowest levels of PFAS or other chemicals of concern possible. Since global legislation varies, global brands are aligning to the strictest legislation. This also ensures that the safe disposal of packaging—whether it is recycled, reused, repurposed, composted, incinerated in waste-to-energy and related systems, or landfilled—ensures a safe supply of recycled and reusable packaging.
The foodservice and retail sectors are making an impact. More than 14 key players such as Burger King, McDonald’s, and Panera Bread are building sustainability strategies around PFAS initiatives. Notably, Panera Bread launched PFAS-free baguette bags in the summer of 2020. Four large U.S. grocery chains now require PFAS-free packaging on private labels. Expansion of foodservice and retailer sustainability initiatives, including chemicals of concern, is needed to link the initiatives related to sourcing (recycled content) and disposal (recyclable) of packaging to the UN's Sustainable Development Goals (SDGs) Target 12 on food waste and more sustainable packaging. This link is critical since recycled content targets should consider the potential of PFAS to be within recycled packaging materials and that these materials should not be in direct contact with certain types of food and only for safe conditions of use.
A Sequence of Assessment, Mitigation, and Control
Assessing which packaging materials are highly probable to contain PFAS and other chemicals of concern is underway. Significantly, this encompasses the consideration of processing aids, inks, adhesives, and other chemicals used in package conversion processes. Next, the levels of PFAS and other chemicals of concern within suspect packaging and food are measured. If PFAS or other chemicals of concern are found, then suitable replacements are made and the packaging value chain is controlled to ensure that PFAS do not reenter the system. Furthermore, comprehensive testing of final packaging is embedded within specifications, qualifications, and standard operating procedures to prevent the reintroduction of PFAS.
Post-Consumer Package Handlers are Taking Action to Halt PFAS Use
At the other end of the value chain, various industry groups have standards for packaging slated for recycling into food packaging or compost of biodegradation. This is "cleaning up" recycled packaging materials and the environment. For example, compostable and biodegradable packaging that may contain PFAS and/or other chemicals of concern is restricted from entering into municipal compost facilities. This avoids contaminating compost used to enhance soil in agriculture with chemicals that can exist in compostable packaging. Likewise, industry recycling certification groups are defining packaging that contains PFAS and other chemicals of concern not to be recyclable.
The distinction between NIAS and IAS within legislative frameworks is fading, and the need for clear restrictions on using PFAS is being addressed. This origin-agnostic approach is essential because it connects the need for a safe environment in which to grow food with the need for safe food-contact packaging and, pragmatically, the need for clear packaging industry guidance on the acceptable levels of PFAS.
In addition, the toxicological impact of PFAS and other chemicals of concern is independent of their IAS or NIAS origins. An aligned value chain of packaging suppliers, brands, retailers, and post-consumer package handlers are prioritizing the replacement of PFAS in packaging. Critically, many innovative solutions require value chain support. As a result, PFAS in food packaging is being addressed earlier than anticipated.
The food packaging industry has the opportunity to lead in educating stakeholders to ensure that rational, defensible, and achievable levels of PFAS and other chemicals of concern are set. We have an opportunity to safeguard food packaging and our food supply.
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Claire Koelsch Sand, Ph.D. is CEO of Packaging Technology & Research LLC, as well as an Adjunct Professor at both California Polytechnic State University and Michigan State University. She has over 35 years of experience in food packaging. She ranks innovative packaging science solutions to extend shelf life and align with consumer needs, generates implementation roadmaps, and aligns business cases. Dr. Sand is an IFT Fellow and a Riester-Davis-Brody Lifetime Achievement in Food Packaging Award recipient. She holds a Ph.D. in Food Science and Nutrition from the University of Minnesota, as well as M.S. and B.S. degrees in Packaging from Michigan State University.