Chemical Structure Data Could Help Protect Us From Harmful Chemicals in Food Packaging
Sorting food contact chemicals into broad structural groups could help regulators prioritize which compounds to test for and assess.
Food packaging and other contact materials—such as paper and plastic packaging, or metal and silicone cookware—can be a source of human exposure to chemicals. After prolonged contact with food or with the heat in the cooking process, some compounds may begin to migrate out of these contact materials and enter our foods before we eat them.
The chemicals present in food contact materials, known as food contact chemicals (FCCs), are often intentionally added to products—they might be the reason why your recyclable paper coffee cup doesn't disintegrate once filled, and why your pan stays non-stick for longer. But while these chemicals do play a useful role in supporting food packaging and kitchenware, very little is known about the overall safety of FCCs; recent analysis suggests that more than 80% of known FCCs lack adequate safety data, with thousands more unidentified FCCs potentially posing additional risks.
In a new study, published in Environmental Science & Technology, researchers from the Food Packaging Forum evaluated whether sorting FCCs into broad priority groups based on their chemical structure could help address current regulatory gaps and improve how potentially hazardous FCCs are screened for and identified. They also present an evidence-based priority list of hazardous FCCs (the FCCprio List) and an open-access interactive application (FCCgroup) that can be used to assist the screening of chemicals of interest.
To learn more about the research and challenges of FCCs' safety, Technology Networks spoke to the study's first author, Dr. Helene Wiesinger, scientific officer at the Food Packaging Forum.
Can you tell us more about FCCs, their origins/uses, and the extent to which they are known to migrate into foodstuffs?
Helene Wiesinger, PhD (HW):
We currently know of around 15,000 FCCs. These are chemicals that are used to produce food contact materials or that have been found to be present in, or migrate from, these materials into food. Food contact materials include everything that comes into direct contact with food, such as packaging, kitchenware, and food-processing equipment. Of these 15,000 FCCs, around 5,000 have empirical evidence of their presence in food contact materials, and 2,159 have been found to migrate into food. The remaining chemicals are listed for use in regulations, technical handbooks, or standards relevant to food contact materials.
Food contact chemicals listed for use in our Food Contact Chemicals database (FCCdb) serve many different functions. They can be used as monomers in plastics and coatings, plasticizers, antioxidants, photoinitiators in printing inks, and for many other applications. However, the traceability of these chemicals remains limited. While around 12,000 chemicals may be used in the production of food contact materials, it is often unclear which are actually used in which products, which remain in the final material, migrate into food, and ultimately contribute to human exposure.
At the Food Packaging Forum, we maintain databases covering both substances that can be intentionally used in food contact materials (the FCCdb) as well as substances that have been empirically detected in, or migrating from, these materials (the FCCmigex). We also compile information on their presence in human biomonitoring studies, known hazards, potential health impacts, and other relevant data.
'The number of empirically detected food contact chemicals has increased substantially in recent years, reflecting both advances in analytical techniques and growing scientific interest in comprehensively characterizing food contact materials. This suggests that our understanding of chemical exposure from these materials remains incomplete and continues to evolve.' — Dr. Helene Wiesinger.
Looking at chemicals with empirical evidence of their presence or migration (around 5,000 FCCs) compiled in our FCCmigex database, there is surprisingly little overlap with chemicals that are intentionally used or listed for use. Many detected substances are non-intentionally added substances (NIAS), including impurities and reaction or degradation products. Their frequent detection highlights that the chemical composition of food contact materials cannot be understood by considering intentionally added substances alone.
AB:
While thousands of FCCs are known, significantly fewer have available hazard data. How does this impact the way that FCCs are assessed by regulators currently?
HW:
For this study, we focused on regulatory-harmonized hazard classifications, which are among the most important data sources used to support regulatory decisions on FCCs and other chemicals, including their restriction or re-assessment. One key finding is that hazard data are not publicly available for many FCCs. As a result, regulatory action can be delayed even when human exposure is highly likely, for example with chemicals that are known to migrate into food.
This challenge is compounded by the fact that chemicals are often still assessed one by one. Even when sufficient hazard data exist and a hazardous chemical is restricted, it may be replaced by a structurally similar alternative for which little or no hazard information is available. This phenomenon, known as regrettable substitution, has been observed with bisphenol A being replaced by bisphenol S [in some products], or the common PFAS compound PFOA being replaced by other shorter-chain PFASs. Because chemical structure often determines both function and toxicity, structurally similar chemicals can also share similar hazards.
This is why our study highlights not only chemicals with known hazards, but also chemicals that belong to structural groups containing many hazardous substances. Such an approach can help identify potential concerns earlier, prioritize testing efforts, and support more preventive chemical management.
AB:
The new study looked at FCC chemical structures and identified 38 priority structural groups containing high volumes of hazardous FCCs. What kinds of structures are reflected in these groups and were there any inclusions that surprised you?
HW:
The priority groups identified in our study include both well-known groups—such as PFASs, ortho-phthalates, toxic heavy metals, and organohalogen compounds—as well as groups that have received much less attention. This includes: acetophenone derivatives, used as photoinitiators in printing inks; organophosphate esters, which are commonly used as alternative plasticizers or can occur as degradation products of antioxidants; and primary aromatic amines, which can originate from azo colorants or polyurethane-based materials. These compound groups are not yet widely discussed in the context of food contact chemicals.
One particularly surprising finding was the prominence of sulfur-containing groups among our priority groups. Several of the identified groups—including isothiocyanates, dithiocarbamates, and sulfinates—contain sulfur. While chlorine-, bromine-, and metal-containing substances are often associated with chemical concerns, sulfur-containing compounds were not initially on our radar, making their frequent appearance among the priority groups especially noteworthy.
AB:
How might a similar structural grouping approach by regulators improve the ways in which FCCs are controlled?
HW:
Assessing chemicals as structural groups rather than one by one can make regulatory assessments more efficient, help prevent regrettable substitution, and identify emerging concerns earlier. By considering groups of structurally similar substances together, regulators can better anticipate where hazardous chemicals may be replaced by alternatives with similar properties and potential risks.
While grouping approaches cannot provide definitive evidence of hazard (or the absence of hazard) for individual chemicals, they can support more precautionary decision-making. They can help regulators and researchers prioritize chemicals and groups for further testing, identify data gaps, and focus regulatory attention.
AB:
Can you tell us more about the FCCprio List and the FCCgroup interactive application, and how these might be used in practice?
HW:
The FCCprio List and FCCgroup app are designed to help different stakeholders identify food contact chemicals that may warrant closer attention. The FCCprio List compiles food contact chemicals with known hazards, while the FCCgroup application allows users to explore whether a chemical belongs to one of the 38 priority structural groups identified in our study, i.e., it is structurally similar to known hazardous chemicals.
In practice, regulators can use these resources to quickly identify chemicals that fall into priority groups and to support decisions on which groups may merit further assessment or regulatory attention. Manufacturers can screen chemicals listed in supplier declarations, ingredients they are using, declarations of conformity, or analytical test results against the FCCprio List and the priority groups to identify substances that may require closer scrutiny.
Researchers can use the tools to interpret large chemical datasets, including non-targeted screening results or chemical databases, to identify substances belonging to priority groups such as PFASs, ortho-phthalates, or organophosphate esters.
More broadly, these resources provide a practical starting point for moving beyond one-by-one chemical assessments and toward a more preventive, group-based approach to chemical management.
AB:
In your opinion, what more needs to be done to protect against human exposure to harmful FCCs?
HW:
Several improvements are needed to better protect people from exposure to harmful food contact chemicals.
First, assessing groups of structurally similar substances together rather than assessing them one by one can help avoid the risk of regrettable substitution. Grouping can also help address data gaps and identify targets for further testing.
Secondly, safety assessments should cover a broader range of health endpoints, including endocrine disruption and other effects, rather than focusing on genotoxicity. For this, high-throughput testing needs to be available.
Thirdly, real world exposure happens to a broad range of chemicals simultaneously, rather than to individual chemicals. Such chemical mixtures (e.g., those that migrate from food contact materials) should be assessed using a mixture assessment factor rather than each chemical in isolation.
Last but not least, food contact materials should be inert and contain as few chemicals as possible. Reducing the complexity of food contact materials and increasing their inertness can be an effective way to reduce chemical exposure.
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