Are we examining compostable packaging, or packaging described as compostable?
An examination of the research, its findings and what they mean for compostability standards, vendors and policy makers. A recent study published in Environmental Science: Advances, titled Are you being served? An examination of chemical risks posed by compostable single-use food service items, raises important questions about the chemical composition of food-service packaging and its suitability for composting. The researchers identified per- and polyfluoroalkyl substances (PFAS), investigated heavy metals and other chemical contaminants, and found conventional plastics in some packaging products and components.
Packaging intended for composting should not introduce substances or materials that compromise the quality of the resulting compost. This principle is reflected in compostability standards, including AS 4736 and AS 5810, which incorporate chemical restrictions and ecotoxicity requirements alongside biodegradation and disintegration testing.
The study essentially asks: What chemical contaminants are present in these packaging products? While the certification framework asks: Does this finished product satisfy the requirements for compostability, including the relevant chemical restrictions and ecotoxicity criteria?
The researchers measured individual PFAS compounds and investigated potential precursors. Those methods can provide information about contamination that total-fluorine screening alone cannot. But they haven't demonstrated whether the tested products held certification, and their measurements don't establish whether the products met or failed the relevant certification requirements.
Consequently, the findings cannot be used to conclude that certified compostable packaging is failing existing certification standards.
Nor can they establish the chemical risks specifically attributable to certified compostable packaging as a product category. The sample set included conventional non-compostable plastics, alongside paper, wood, bagasse and other materials whose finished-product certification status was not documented.
The researchers identified substances and materials of concern in individual products, but without establishing what those products were, how they were represented or whether they were certified, it is not possible to determine what these findings reveal about the chemical safety of certified compostable packaging.
Suppose a genuinely certified product contained detectable PFAS at concentrations below the applicable total-fluorine threshold, with no evidence of intentional addition.
That wouldn't necessarily represent a certification failure. But it could raise a legitimate question about whether existing certification criteria are sufficiently protective for the intended end use. And that is a scientifically worthwhile question because compliance with a standard and the adequacy of that standard are two different questions.
But the certification status of individual products was not established in the published sample records. We cannot know whether the individual products examined were independently certified compostable, merely described as compostable, or conventional packaging products. And remarks throughout the paper suggest that it was not fully known.
Figure 1. Materials identified in the 16 food-service packaging lids examined in the study. Source: Wotton et al., Environmental Science: Advances (2025). https://doi.org/10.1039/d5va00195a
The researchers' own material analysis illustrates this distinction. Of the 16 lids examined, seven were made from materials classified as potentially compostable, while nine were made from conventional plastics or could not be identified. Importantly, the classification was based on material composition rather than verified finished-product certification.
What did the researchers examine?
The study collected 162 food-service items from several sources, including vendors at three Australian universities, two additional institutional environments and a major compostable-packaging supplier.
From these, the researchers selected a subset of 50 products for chemical analysis and material characterisation, covering bowls, containers, clamshells, trays, paper straws, cutlery, napkins, wraps, bags, cups and lids. The selection included paper, cardboard, bagasse (sugarcane fibre), wood and plastic-lined packaging.
While the researchers describe selecting products to avoid duplication and represent different packaging materials and formats, the published methodology provides limited detail about how the original 162 items were reduced to the 50 presented in Table 1. This is important because that selection process influences how the results can be interpreted, particularly when comparing the prevalence of contaminants across different material categories.
Table 1. Number of each item and material analysed in the study. Source: Wotton et al., Environmental Science: Advances (2025). https://doi.org/10.1039/d5va00195a
The five plastic-lined paper cups included in Table 1 were examined for plastics only, rather than the other contaminants of concern. The researchers also examined 16 lids in a separate material analysis. They reported that matching lids to their corresponding vessels was not possible for some items collected from institutional back-of-house areas or directly from the packaging manufacturer.
Interestingly, discussions with university food-service operators revealed two possible reasons for the presence of conventional plastic lids on potentially compostable containers.
Some operators reported that compostable lids deformed when stored on top of coffee machines. Others described having limited control over the packaging supplied by distributors, who sometimes provided conventional plastic lids compatible with compostable vessels.
These observations raise questions about how institutional waste-reduction programmes are implemented and monitored, particularly where procurement requirements specify compostable packaging.
What chemicals were analysed
The researchers used several analytical techniques to identify chemical contaminants and characterise packaging materials, including coatings and polymer layers. Their investigations included targeted analysis of 38 PFAS compounds, additional testing for potential PFAS precursors, and analyses of heavy metals, phthalates and material composition.
The resulting data provide useful information about the substances present in the sampled products. However, the published sample decoder records only broad product categories, material classifications and whether products were printed. It does not identify individual manufacturers, suppliers, product specifications, environmental claims or certification status.
This matters because the primary material of a product does not establish its complete composition or compostability. A paper cup may contain a polyethylene lining. A wooden utensil may have an additional coating. A bagasse container may contain chemical treatments intended to provide grease or water resistance.
Understanding the composition of these products is important. Understanding what manufacturers claim about them, and whether those claims have been independently verified, is equally important.
The absence of this product-level information limits our ability to establish whether the sampled products met the requirements of compostability certification or the procurement policies of the institutions from which they were collected.
PFAS findings
Targeted PFAS were detected in eight of fourteen bagasse samples, one of five cardboard samples and one of fifteen paper samples. No targeted PFAS were detected in the plastic-lined or wooden samples examined using this method. These findings demonstrate variation between products classified under the same broad material category.
However, the material classifications require careful interpretation. For example, Table 1 groups five sandwich wraps and bags as paper and one as plastic-lined. The classification alone does not establish whether the paper products contained additional coatings, treatments or adhesives. And likewise, the plastic-lined category includes products whose polymer composition may differ.
Without detailed product specifications, it is difficult to determine which materials or manufacturing processes contributed to the chemical findings.
Figure 3. PFAS concentrations for each sample examined separated by material type and PFAS species. Source: Wotton et al., Environmental Science: Advances (2025). https://doi.org/10.1039/d5va00195a
The detection of PFAS in these samples warrants further investigation. However, without verified product certification information and directly comparable testing, these results cannot establish whether individual products failed the requirements of AS 4736 or AS 5810.
Metals
The researchers also analysed metal concentrations across the sampled materials, finding considerable variation between material categories. Cardboard products had the highest average concentrations of several measured metals. The researchers suggest that these findings may be associated with impurities in recycled fibre, additives used during manufacturing, or inks and dyes applied during printing.
However, the study does not establish the recycled content or detailed manufacturing specifications of the individual products. Although the sample records identify whether products were printed, they do not document ink formulations, colours, print coverage or placement. These details would be useful in investigating the possible sources of the detected metals.
The researchers reported no concentrations above the laboratory reporting limits for silver, arsenic, beryllium, cadmium, mercury, molybdenum or selenium. Importantly, the presence of metals does not, in itself, establish that a product is unsuitable for composting. Australian compostability standards AS 4736 and AS 5810 include restrictions on specified metals and ecotoxicity requirements intended to assess potential adverse effects on the resulting compost and biological organisms.
The study's comparison of average metal concentrations across broad material categories does not establish whether individual products exceeded the applicable certification limits. Nor does it establish whether any sampled products had undergone the relevant finished-product certification assessments.
Coatings, inks and adhesives
The researchers also investigated the presence of coatings, inks and adhesives in selected food-service products, identifying additional materials that were not apparent from their primary composition. Again there was no documentation in the methodology or supplement materials to understand the coatings, inks and adhesives present in the samples.
Raman spectroscopy identified signals consistent with polystyrene and polystyrene/acrylate composites between the paper layers of two of the four straws examined. The researchers suggest these materials may be associated with adhesives used to bond the layers together.
Analysis of three coloured paper straws also identified surface materials consistent with plastic-based polymers, including styrenated pigments used in printing inks.
Separately, FTIR analysis of a wooden cutlery sample identified spectral characteristics consistent with a possible oil, wax or polyethylene coating. The researchers could not conclusively identify the coating material. These findings demonstrate why describing a product as paper or wood does not necessarily establish its complete material composition.
Figure 10. The overlayed normalised FTIR spectra of coated cutlery (cutlery-5) and uncoated cutlery (cutlery-3). Source: Wotton et al., Environmental Science: Advances (2025). https://doi.org/10.1039/d5va00195a
The researchers also raise concerns about provisions within AS 4736 that allow certain constituents representing less than 1% of a product's total mass to be excluded from individual assessment. This may be relevant to low-volume materials such as inks, adhesives and coatings.
However, an exemption from individual constituent testing should not be confused with an exemption from all finished-product certification requirements, including applicable chemical restrictions and ecotoxicity assessments. The precise scope of this provision warrants further examination.
Compostable materials are not necessarily certified compostable products
Compostability describes a product's ability to biodegrade under specified composting conditions and within a defined timeframe, while meeting other relevant requirements for compost quality.
However, a material's potential to biodegrade does not establish that a finished product is compostable, or that it has been independently certified against a recognised standard.
In Australia, AS 4736:2006 and AS 5810:2010 establish requirements for industrial and home compostability respectively. These standards assess more than whether a material breaks down. Their requirements include biodegradation, disintegration, restrictions on specified chemical constituents and ecotoxicity testing.
The presence of a material such as PLA, bagasse, paper or wood does not, by itself, demonstrate that a finished product meets either standard. Coatings, inks, adhesives and other components can influence its suitability for composting. The researchers acknowledge some of this uncertainty by describing certain materials as potentially compostable. This is appropriately cautious where product certification has not been established, but it also highlights an important limitation of the research.
The published sample records do not identify which individual products, if any, were independently certified as compostable. Consequently, the study cannot determine whether certified products failed to meet applicable requirements, uncertified products were marketed as compostable, or conventional packaging was supplied in place of compostable alternatives. These circumstances have different implications and require different responses.
What do the chemical findings tell us about certification?
The study's PFAS findings are particularly relevant here. The researchers used targeted analytical methods to investigate individual PFAS compounds, alongside other techniques to examine fluorine and potential PFAS precursors. These approaches provide valuable information about the chemical composition of the sampled products.
However, individual PFAS concentrations cannot be directly compared with the total-fluorine threshold referenced in Australian compostability requirements. These measurements assess different things, using different methods and units. There is also an important distinction between detecting a PFAS compound and establishing that it was intentionally added during manufacture. Trace contamination may originate from raw materials, recycled feedstocks, water or manufacturing processes. This has been found to be the case for recycled materials for example.
That distinction however should not diminish the significance of the study's findings. The elevated surface fluorine concentrations identified in certain bagasse products, together with the results of precursor analysis, raise serious questions about the possible use of fluorinated treatments in particular, in molded fibre packaging.
These concerns are not new. An Australian Government packaging reform consultation document referenced earlier research identifying PFAS in fibre-based food packaging, with the highest levels found in bagasse takeaway containers. It also noted APCO's industry-led initiative to phase out PFAS in fibre-based food-contact packaging by the end of 2023.
The study's findings therefore reinforce an existing area of concern and warrant further investigation, including verification of the products' formulations and certification status.
The researchers also question whether compostability standards adequately assess inks, adhesives and other constituents used in small quantities, referring to a provision in AS 4736 concerning constituents representing less than 1% of a product's mass.
However, exemption from individual biodegradation testing does not necessarily mean exemption from certification assessment. For example, the European Bioplastics industrial compostability certification scheme requires disclosure of additives below 1%, documentation of coating composition and thickness, relevant safety information and testing of the coated product. Additional ecotoxicity testing may be required where the suitability of a substance cannot otherwise be established.
These requirements do not eliminate the need to investigate the environmental implications of low-volume additives. They do, however, demonstrate why it is important to distinguish between the absence of individual biodegradation testing and the absence of assessment altogether. But whether a product complies with a compostability standard and whether that standard adequately addresses all relevant environmental risks are separate questions.
The study contributes evidence to the second question, but without identifying certified products and assessing their results against the applicable requirements, it cannot establish failures of certification compliance or determine whether the identified chemical concerns are attributable to certified compostable packaging.
An opportunity to examine institutional procurement
Another important aspect of the study is where the packaging was collected. The researchers obtained products from university food-service vendors and other institutional environments operating within broader sustainability and waste-reduction programmes.
The University of New South Wales has implemented a Plastic Free Dining initiative. At the University of Technology Sydney, certified compostable takeaway packaging requirements have been incorporated into leases for food retailers within UTS Central. The University of Sydney has also published guidance on compostable packaging and the distinction between industrial and home compostability. And these initiatives provide important context for the research.
Universities can establish procurement policies and sustainability commitments, but their effectiveness depends on the products actually supplied and used. The study identified conventional plastic lids paired with potentially compostable vessels. The researchers also reported difficulties identifying certain materials, including products that appeared to be compostable alternatives but were subsequently identified as conventional polymers. These findings raise questions about how food-service packaging is selected, supplied and verified.
If conventional packaging is supplied where certified compostable products are required, the problem may involve procurement practices, supplier substitutions, product availability or inadequate verification.
If a certified product contains substances of concern, the implications may instead relate to manufacturing controls, certification requirements or the environmental performance of that product.
The study could potentially have helped distinguish between these circumstances. However, the published methodology does not establish whether each sampled product was subject to a particular institutional procurement requirement, nor does it provide the product-level information necessary to verify supplier claims or certification.
We therefore cannot determine whether the conventional materials identified represent breaches of university procurement policies. That said, the findings raise an important question:
When an institution (or a venue, a lease holder or an event), requires compostable packaging, what evidence demonstrates that the products actually supplied meet those requirements?
Why product identification matters
The researchers' analytical methods provide considerable detail about the chemical and material composition of the sampled packaging. Comparable attention to product identification would have made these findings more actionable and valuable. For each product, information about its manufacturer, supplier, material specifications, coatings, marketed claims and certification status would have provided a basis for interpreting the laboratory results.
This is particularly important for unbranded food-service packaging. A paper straw, wooden utensil or sugarcane container may carry no information identifying its manufacturer or supplier. Those details often need to be obtained from the vendor or distributor at the point of collection.
The study also illustrates why the primary material alone is insufficient. The researchers identified possible surface coatings on wooden cutlery, polymer-based materials in paper straws and conventional plastics in products that could otherwise be mistaken for compostable alternatives.
These findings demonstrate the importance of examining the finished product rather than relying on appearance or broad material descriptions. Where specifications or certification records could not be obtained, documenting that absence would itself have provided useful evidence about supply-chain transparency. The missing information also limits the policy conclusions that can be drawn from the research.
Australia already has consumer-law requirements concerning misleading environmental claims, alongside voluntary independent compostability certification schemes. The presence of incorrectly described or unsuitable products may indicate problems with claim substantiation, procurement or enforcement. It does not necessarily establish an absence of regulation.
Understanding which of these problems is occurring is essential to identifying an effective response. This also has broader policy implications.
What does this mean for composting and organics recovery?
The study raises legitimate concerns about substances and materials that may enter organic waste streams through food-service packaging. However, identifying a chemical constituent in packaging does not, by itself, establish how much will enter finished compost or what environmental consequences may follow. Those outcomes depend on the quantities of packaging entering a composting system, the concentrations and properties of individual substances, processing conditions and subsequent exposure pathways.
These concerns are already recognised in Australian packaging policy discussions. The Australian Government's packaging reform consultation document identified the removal of PFAS and other chemical additives of concern as a potential opportunity to support the recovery of compostable packaging through kerbside organics collections while protecting compost quality.
Broader national packaging reform discussions have also considered restrictions on problematic materials and chemicals. However, these proposals should be distinguished from measures already implemented. Further research into these questions is important, particularly where findings suggest fluorinated treatments or persistent polymer-based constituents.
What did the study really establish?
Are you being served? provides valuable evidence of chemical constituents, coatings and conventional polymers in a selection of takeaway food-service packaging collected from university vendors, other institutional environments and a packaging supplier.
The products represented a mixture of materials, including conventional plastics and materials considered potentially compostable, rather than a verified sample of independently certified compostable packaging.
Some findings are significant and warrant further investigation, particularly those involving elevated fluorine concentrations in bagasse products and polymer-based materials in paper straws. The research also highlights practical difficulties in identifying packaging materials and distinguishing potentially compostable products from conventional alternatives.
However, the study's framing concerns chemical risks associated with compostable food-service packaging, while its published sample records do not establish which products were independently certified as compostable. The sample set includes identified conventional and non-compostable materials, potentially compostable materials and products of unknown certification status.
And that is really important because the study cannot reliably establish whether its findings reveal shortcomings in certification requirements, unsupported compostability claims or failures in procurement and supply-chain verification.
Research that connects chemical analysis with verified product specifications, certification records and institutional purchasing requirements would provide a stronger foundation for understanding the sources of contamination and identifying where intervention is needed.
The objective should not simply be to identify what is present in food-service packaging, but to understand what each product was intended to be, whether it met the requirements placed upon it and what its composition means for the systems in which it is used. That is how research can better inform environmental standards, procurement practices and organics recovery.
The findings also have implications for broader packaging regulation. Australian Government consultations on national packaging reform have considered restrictions on problematic materials and chemicals, including options for Commonwealth legislation and extended producer responsibility.
These proposals reflect growing attention to the chemical composition of packaging, beyond its recyclability or compostability. However, proposed reforms should be distinguished from requirements already in force.
The study's findings could contribute to this discussion, particularly where substances of concern are identified in food-service packaging. Establishing the identity, composition and certification status of those products would help policymakers determine whether additional chemical restrictions, stronger verification requirements or improved enforcement would be the most appropriate response.
