Antioxidants are widely used in polymer formulations to protect products and materials, including those in food contact, from oxidative damage. They have been detected in various natural environments and in migrates of food contact materials (FCMs) leading to documented human exposure. While some antioxidants have been well characterized and are restricted for certain uses or banned altogether, for the majority, their impacts on human and environmental health remain poorly understood.
The majority of antioxidants are hazardous
Scientists from the University of Zürich and ETH Zürich assessed the hazards of 507 natural and synthetic antioxidants and nine transformation products, considering their recalcitrance to mineralization (not readily biodegradable), persistence (P), toxicity toward humans and aquatic organisms (T), bioaccumulation potential (B), and mobility (M). In their article published on March 2, 2026, in the journal Environmental Science & Technology Letters, Carolin Seller-Brison and co-authors report that 74.4% of the assessed antioxidants are toxic, while 61% are not readily biodegradable. Overall, 4.8% and 2.1% of the antioxidants were classified as PBT or PMT substances, respectively.
Since the European Union adopted PMT and PBT as new hazard classes in 2023, these substances are considered to be of high concern under EU regulation. Most of the identified PBT and PMT substances were primary antioxidants (phenolic and amine compounds belonging to the groups “hindered phenol derivatives” and “secondary aromatic amines”).
In contrast, the researchers identified both primary and secondary antioxidants of natural origin (or “nature-identical”), such as esters and organic sulfur compounds, to be less frequently classified as hazardous, indicating more favorable chemical structures with respect to safety. Overall, only 19 of the more than 500 evaluated antioxidants were categorized as non‑toxic. The assessment was based on scientific literature, regulatory databases, and the use of in silico tools such as the US Environmental Protection Agency’s BIOWIN to address data gaps.
Antioxidants are particularly prone to migrate from starch-based biodegradable plastics
In another recent study, Liqian Wang and co‑authors evaluated 39 Chinese disposable food contact products designed for biodegradation (e.g., takeaway boxes, plates, forks, and straws) for the migration of antioxidants. They focused on 17 antioxidants permitted for use in FCMs in China, two degradation products, and one compound commonly detected in FCMs. In an article published on March 9, 2026, in the journal Foods, they reported detecting ten antioxidants in their products. Sixteen of the 39 tested products contained two or more antioxidants.
When comparing samples of different material types, Wang and co-authors found that all starch‑based products (including plateware and cutlery) contained antioxidants, whereas only half of the polylactic acid‑based (PLA) products and none of the fiber‑based products did. They hypothesized that the greater prevalence of antioxidants in starch‑based products is due to the presence of hydroxyl groups, which make these materials more susceptible to oxidation, as well as their porous structure, which may favor migration.
PLA is a chemically synthesized polyester, while “starch-based plastic” is usually a blended material in which native starch (often thermoplastic starch, TPS) is the main component, but is combined with other polymers, such as PLA or polybutylene adipate terephthalate (PBAT), the latter being made from fossil carbon, while PLA and TPS are made from renewable carbon. PLA and PBAT are fully synthetic polymers, while TPS retains the native biopolymer structure of starch, leading to its fast biodegradation. The starch-based products in Wang et al.’s study included unspecified starch, corn starch, and mixes of starch and various polymers.
Across all products, ten out of the 20 tested antioxidants were identified. Most of these were hindered phenols and amines, which were more likely to be classified as hazardous according to the assessment by Seller‑Brison and co‑authors. Irganox 1010 (CAS 6683-19-8), a chemical identified as a potential mammary carcinogen (FPF reported), and Irganox 1076 (CAS 2082-79-3) were the most frequently identified antioxidants, and they were often detected in combination with Irgafos 168 (CAS 31570-04-4).
Wang and co-authors further calculated the exposure risk of detected antioxidants following the guidelines of the US Food and Drug Administration and the European Food Safety Authority based on estimated daily intake and the no observed adverse effect level. Overall, they found the exposure risk to be low. “However, Monte Carlo simulation analyses indicated that exposure to high doses of Irganox 1010 in both 95% ethanol and soybean oil could pose health risks.” The simulants 95% ethanol and soybean oil are used to represent foods with high fat contents, implying that Irganox 1010 migration into such foods may exceed safe thresholds.
Considering hazards beyond toxicity, the assessment by Seller-Brison and co-authors classified Wang et al.’s three most commonly identified substances (Irganox 1010, Irganox 1076, and Irgafos 168) as PBT substances, with Irganox 1010 also classified as persistent and toxic. Furthermore, all three compounds were classified as not readily biodegradable. This highlights the importance of considering hazards beyond toxicity to obtain a more comprehensive picture of their potential impacts on human and environmental health.
References
Seller-Brison , C. et al. (2026). “Hazard Assessment of Antioxidants as Contaminants of Concern.” Environmental Science & Technology Letters. DOI: 10.1021/acs.estlett.5c01217
Wang, L. et al. (2026). “Migration and Safety Assessment of 20 Antioxidants in 39 Disposable Biodegradable Tableware Products.” Foods. DOI: 10.3390/foods15050964
