Recycling is often seen as a key solution to plastic pollution by keeping materials in the loop. Polyethylene terephthalate (PET) is currently the most widely recycled plastic for food-contact applications. However, growing scientific evidence shows that plastic recycling poses chemical safety challenges (FPF reported and here). Three peer-reviewed studies published in October and November 2025 reinforce safety concerns about the use of recycled PET in food contact.
Virgin and recycled PET differ in chemical composition
In an article published October 23, 2025, in Environmental Science Processes & Impacts, Yanan Li from Toronto Metropolitan University, Canada, and co-authors reported that virgin PET (vPET) and recycled PET (rPET) differ in their chemical profiles. The researchers analyzed 18 PET bottles, half with recycled content, purchased in Michigan and Oregon for 124 Persistent, Mobile, Toxic (PMT) plastic additives, 23 per- and polyfluoroalkyl substances (PFAS), 26 organophosphate esters (OPEs), and 20 non-intentionally added substances (NIAS). They detected 12 PMTs, six OPEs, and 15 NIAS.
Concentrations of ethylene glycol (CAS 107-21-1), a PET monomer, and 2-methyl-1,3-dioxolane (CAS 497-26-7), a polymerization byproduct, were higher in vPET. Benzene, a carcinogen, was present in all rPET but only in one vPET bottle. The authors describe that benzene is introduced during recycling when chlorine-containing materials like polyvinyl chloride (PVC) contaminate the PET stream. At high temperatures, PVC dehydrocholinates and forms hydrochloric acid, which most likely catalyzes the conversions of PET into benzene according to a study cited by Li and co-authors.
OPEs are used as substitutes for brominated flame retardants and may also act as plasticizers. These flame retardants have been detected in paper and board food contact materials, plastics, multi-materials, and metals. They may originate from organophosphite antioxidants (OPAs) which are commonly added to polymeric materials to slow down aging and are naturally oxidized to OPEs. Their exposure has been linked to neurotoxicity and endocrine disruption (FPF reported), especially when exposures occur during prenatal development (FPF reported). In rPET, OPEs were more prevalent (54%) than in vPET products (36%), but concentrations were low. Previous studies have shown OPEs are more frequently detected in recycled than virgin plastics (FPF reported). Foodstuffs are commonly contaminated with OPEs (FPF reported), and plastic food packaging was uncovered as a source (FPF reported).
Li and co-authors also measured antimony (CAS 7440-36-0) levels, which were similar in both PET types. In another experiment, bioassays revealed endocrine-disrupting activity of mixtures of migrating PET chemicals, with no clear difference between vPET and rPET. Given the chemical complexity of the investigated products, the authors call “for standardization of plastic additive uses in plastic products.” Besides the additives, also the quality of starting substances, and processing aids such as catalysts need consideration since they contribute to NIAS formation and increase chemical complexity.
For the analysis of PMT substances, PFAS, and OPEs, they used high-performance liquid chromatography coupled with quadrupole time-of-tight mass spectrometry (HPLC-QToF-MS) after leaching PET bottles for up to 34 days in water simulating a day-night cycle and shaking at 30 rpm. NIAS were extracted with tetrahydrofuran or water and analyzed via gas chromatography coupled with mass spectrometry (GC-MS).
Recycling increases chemical contamination
Fabiana Di Duca from the University “Federico II”, Naples, Italy, and co-authors investigated contamination sources during the recycling chain. In an article published November 22, 2025, in the Journal of Chromatography, they describe the collection of samples at key stages of the rPET recycling process: initial flakes, intermediate granules, and final preforms (50:50 vPET/rPET and 100% rPET).
Targeting NIAS and specifically volatile organic compounds (VOCs) and phthalate acid esters (PAEs), the scientists found both types of compounds at levels that increased along the recycling process: vPET granules < rPET flakes < rPET granules < 50:50 vPET/rPET preforms < 100 % rPET preforms. This finding confirms previous observations that concentrations of many chemicals are higher in recycled materials (FPF reported). Di Duca and co-authors hypothesize that the compounds likely originate from thermal degradation during processing, contamination from previous uses, and adsorption of external substances after use, as well as incomplete purification.
The PET monomer ethylene glycol was present at the highest concentrations across all samples, followed by the polymerization byproduct 2-methyl-1,3-dioxolane, benzaldehyde (CAS 112-41-4; byproduct of PET processing a recycling formed though the oxidation of aromatic compounds), and benzene. Interestingly, Di Duca and colleagues identified the same or similar compounds as Li et al., but in different distributions between vPET and rPET. Di Duca and co-authors further reported that the PAE dibutyl phthalate (DBP, CAS 84-74-2) was present at the highest levels among all analytes in concentrations, with up to 0.98 mg/kg plastic in 100% rPET preforms, followed by dimethyl phthalate (DMP, CAS 131-11-3) with up to 0.39 mg/kg, also in 100% rPET preforms. DBP is a known endocrine disruptor. It is identified as priority contaminant in rPET by EFSA’s guidance document to evaluate the safety of post-consumer mechanical PET recycling processes intended to be used for manufacture of materials and articles in contact as DBP “found to persist or accumulate in rPET matrices despite the recycling steps,” as highlighted by Di Duca and co-authors.
The authors conclude that their “findings emphasize the need for stricter monitoring, regulatory frameworks, and more effective decontamination strategies to ensure that the environmental benefits of PET recycling are not achieved at the expense of consumer health.” Researchers have already provided policymakers with five steps for addressing hazardous chemicals in recycled plastics (FPF reported).
All samples Di Duca and co-authors investigated were “from a well-established producer within the European Union” and intended for food contact, with rPET samples derived from mechanical recycling. VOCs were analyzed using a Purge and Trap (P&T) system coupled to GC-MS. For PAE assessment, samples were extracted with dichloromethane before GC-MS.
Method to quantify recycled content in PET
Blas Rocamora-Rivera and co-authors from the University of Murcia, Spain, developed a method to quantify recycled content in PET. Published on November 25, 2025, in the Microchemical Journal their approach uses headspace gas chromatography coupled with ion mobility spectrometry (HS-GC-IMS) to monitor 16 VOCs. Testing trays made of vPET, 60% rPET, and 100% rPET demonstrated higher VOC concentrations in recycled PET. They consider their approach promising to help enforce compliance with recycled plastic regulations.
In 2022, the European Commission adopted Regulation (EU) 2022/1616 on recycled plastic materials and articles intended to come into contact with food (FPF reported). In September 2025, Türkiye amended its food contact materials regulation to allow recycled plastics (FPF reported). A recent report by Greenpeace USA found that plastic recycling does not work as promised in the US, and analyzes several false claims made in this context (FPF reported).
References
Di Duca, F. et al. (2025). “Occurrence of volatile organic compounds (VOCs) and phthalate acid esters (PAEs) in recycled PET: Implications for food packaging materials.” Journal of Chromatography A. DOI: 10.1016/j.chroma.2025.466433
Li, Y. et al. (2025). “Emerging investigator series: unpacking PET: comparative analysis of leachable and extractable contaminants from virgin and recycled polyethylene terephthalate bottles and textiles.” Environmental Science Processes & Impacts. DOI: 10.1039/d5em00615e
Rocamora-Rivera, B. et al. (2025). “Gas chromatography-ion mobility spectrometry for the quantification of recycled polyethylene terephthalate in food packaging.” Microchemical Journal. DOI: 10.1016/j.microc.2025.116332
