Food processing chemicals, particularly those from food contact materials (FCMs), are a growing area of concern regarding human health. Understanding the extent to which humans are exposed to these chemicals is crucial for effective risk management and public health protection. This article delves into the relevance of human exposure to food processing chemicals, drawing on recent research and databases to highlight key findings and knowledge gaps.
The Scope of Human Exposure to Food Contact Chemicals
Recent studies have revealed that a significant number of food contact chemicals are detectable in humans, raising concerns about potential health impacts. Research indicates human exposure to at least 25% of known Food Contact Chemicals (FCCs). While food is not the only exposure pathway for these chemicals, FCMs are a likely and significant source. A novel database, FCChumon, has been developed to track FCCs monitored in humans. This database, when integrated with FCCmigex, a database of chemicals migrating from FCMs, allows for targeted research into human exposure from FCMs and helps identify critical knowledge gaps. These resources are essential for understanding the health implications of FCCs and prioritizing future research.
Parent Compounds vs. Metabolites: Implications for Exposure Assessment
Assessing human exposure to food processing chemicals is complex, especially when considering metabolism. For chemicals like phthalates and volatile organic compounds (VOCs), human biomonitoring often focuses on metabolites rather than the original parent compounds. This is because metabolites are sometimes more readily detectable and can provide a more accurate picture of exposure. While tools exist to predict chemical biotransformation and identify metabolites, these methods come with considerable scientific uncertainty. For example, predicting the metabolism of agrochemicals and flame retardants has proven challenging. This study acknowledges the metabolite aspect but primarily focuses on parent compounds due to the vast number of FCCs analyzed and the limitations in systematically predicting all potential metabolites. Only readily available metabolite information from biomonitoring programs was considered.
Key Chemical Groups of Concern in Food Processing and Human Exposure
Certain groups of food processing chemicals are recognized as significant contributors to human exposure. These include phthalates and their alternatives, metals, VOCs, and phenolic compounds. These substances are frequently found in FCMs and are routinely detected in human biomonitoring studies. Evidence of their migration from packaging into food is well-documented. Per- and polyfluoroalkyl substances (PFAS) are another group of concern. Despite limited authorization for food contact use, PFAS contamination from food packaging is a recognized exposure pathway. Dioxin-like compounds, pesticides, and flame retardants, while not intentionally added, can also find their way into FCMs through manufacturing, use, and recycling processes, further contributing to human exposure. While FCMs can contribute to human exposure to intentionally used FCCs, non-intentionally added substances (NIAS), and even illicit chemicals, the precise contribution of FCMs to the overall human body burden for most FCCs remains unclear.
Phthalates and Alternatives
Phthalates are well-known plasticizers that have been widely used in food packaging. Human exposure is common, and concerns exist regarding their endocrine-disrupting properties. Alternatives to phthalates are also being monitored, as some may pose similar health risks.
Metals
Metals can migrate from FCMs, particularly metal packaging and cookware. Exposure to certain metals, like aluminum, can pose health risks if levels are high.
Volatile Organic Compounds (VOCs)
VOCs can originate from various FCMs, including plastics and adhesives. Exposure can occur through inhalation and ingestion, with some VOCs linked to adverse health effects.
Phenolic Compounds
Phenolic compounds, such as bisphenol A (BPA), are used in some FCMs, like polycarbonate plastics and epoxy resins. BPA is an endocrine disruptor, and its presence in food and human exposure are significant concerns.
Per- and Polyfluoroalkyl Substances (PFAS)
PFAS are a class of persistent chemicals used for grease-proofing in food packaging. They are highly persistent in the environment and human body, with potential links to various health issues.
Dioxin-like Compounds, Pesticides, and Flame Retardants
These chemicals are not intentionally added to FCMs but can contaminate them during production or recycling. They represent non-intentional exposure routes through food packaging.
Antioxidants in Food Packaging: An Overlooked Exposure Pathway
Antioxidants deserve special attention due to their widespread use in plastic food packaging and high production volumes. They are added to polymers to prevent degradation and extend the shelf life of FCMs. Significant evidence confirms their presence in FCMs. Sterically hindered phenols and phosphite antioxidants are particularly common. Examples include Irgafos 168, Irganox 1076, and Irganox 1010. However, these specific antioxidants are not routinely included in biomonitoring programs or exposome databases. Limited research has directly detected these parent antioxidants in humans. Interestingly, degradation products of these antioxidants, such as 2,4-di-tert-butylphenol, 2,6-di-tert-butylbenzoquinone, and tris(2,4-di-tert-butylphenyl)phosphate, have been detected in human urine in some studies, sometimes at high concentrations. This suggests that human exposure to antioxidants and their breakdown products from FCMs might be underestimated and warrants further investigation. The contribution of FCMs to human exposure to antioxidants and their metabolites is an area needing more focused research.
Oligomers and BADGE Derivatives: Emerging Concerns
Oligomers, such as PET, PA, and siloxane oligomers, are byproducts of polymerization processes and have been found migrating from FCMs. However, evidence of their presence in humans is scarce, possibly due to analytical challenges in detecting oligomers in complex biological samples and the limited availability of reference standards for identification and quantification. Bisphenol A diglycidyl ether (BADGE) and its derivatives are also concerning. BADGE derivatives are formed during the production of epoxy resins, commonly used in food can linings and coatings. These derivatives have been linked to toxic effects like endocrine disruption and genotoxicity, although toxicity data remain limited. While several BADGE derivatives have been found in FCMs, only a few have been detected in humans. This highlights the need for targeted analysis of structurally related chemicals, such as polymerization byproducts, to bridge the knowledge gap on human exposure to these compounds.
Photoinitiators: Widespread Use and Potential Exposure
Photoinitiators are a diverse group of FCCs used in coatings, printing inks, and adhesives for FCMs. While their presence in FCMs is well-established, human exposure has not been as extensively studied. Recent research has detected photoinitiators and their metabolites in human serum. Benzophenone, a commonly used photoinitiator in FCMs, is of particular concern. It is classified as a presumed carcinogen and a suspected endocrine disruptor. Given its frequent detection in FCMs and potential hazards, exposure to benzophenone from FCMs should be minimized.
Limitations in Data Interpretation
Interpreting data on human exposure to food processing chemicals requires acknowledging certain limitations. The data sources used to compile FCChumon vary in their chemical scope, data curation rigor, and level of detail. Biomonitoring programs are generally considered highly reliable due to their representative populations and strict analytical protocols. However, they typically monitor only a limited number of chemicals. Systematic evidence maps offer a robust approach but may lack the quality assessment of individual studies. Metabolome and exposome databases, while comprehensive, may include data from diverse sources and automated approaches, requiring further review for accuracy. Furthermore, some FCCs are complex mixtures (e.g., polymeric molecules, isomers), making CAS number conversion and identification challenging, potentially leading to underreporting in certain databases. Examples include chlorinated paraffins and nonylphenol, where mixture complexity affected database searches but were identified through literature reviews.
Implications for Risk Management and Policy
The evidence presented strongly suggests that FCMs contribute to human exposure to a wide range of FCCs. Because many of these chemicals possess hazardous properties, restricting their use in FCMs is crucial to minimize human exposure. Regulatory discussions are underway for certain high-concern chemicals like PFAS, BPA, and phthalates. However, it’s important to recognize that the absence of biomonitoring or hazard data for many other FCCs does not imply safety. Significant data gaps exist, even for chemicals with some hazard data available. Filling these data gaps, particularly for intentionally added FCCs like antioxidants and photoinitiators, and NIAS such as oligomers and BADGE derivatives, is a high priority for accurate risk assessment and human health protection. Comprehensive hazard data are essential to characterize the risks posed by FCCs migrating into food.
Conclusion
This study systematically maps a significant number of food contact chemicals for which human exposure evidence exists, alongside a larger group where evidence is still lacking. It highlights a subset of FCCs of high concern due to their hazardous properties and underscores substantial data gaps regarding hazards and human health risks. The freely accessible FCChumon dashboard, along with the FCCmigex database, provides valuable resources for prioritizing FCCs for further investigation. These databases support informed policy and decision-making and emphasize the urgent need for stricter regulations, potentially including bans on the most hazardous chemicals migrating from food packaging and other FCMs into food. Protecting human health necessitates a proactive approach to minimizing exposure to harmful food processing chemicals.
