PLA bioplastic misconceptions
PLA is one of the most widely used bioplastics in foodservice packaging, but the terms bioplastic, bio-based, biodegradable and compostable are often used interchangeably when they describe different things. Discovered in the 1930s, PLA is a bio-based plastic most frequently made from renewable plant feedstocks such as corn starch or sugarcane. When a PLA product is certified compostable, it has been independently tested against specified criteria for biodegradation, disintegration and compost quality under defined composting conditions.
Much of the confusion arises when the properties of the material are separated from the systems required to recover it. A product can be certified compostable while still not being accepted by a particular industrial composting facility or collection service. Research conducted by Scion demonstrated that concern amongst organics recyclers that PLA may negatively impact end product quality, is in fact, operational processing variances from the Compost Standards.
Here we look at six common misconceptions about PLA and compostable bioplastics and the distinction between the material, its certifications and the infrastructure available to process it.
#1: PLA packaging is greenwashing
Reality: PLA packaging certified for compostability is designed for recovery through composting, including alongside food scraps. The European compostability standard EN 13432 was developed in response to the European Packaging and Packaging Waste Directive 94/62/EC, establishing requirements for packaging recoverable through composting and biodegradation. In Europe, mandatory organics collections and an established composting infrastructure are supported by policies that enable certified compostable packaging to be managed through this end-of-life pathway.
READ: Compostable materials in the real world: Scion x WasteMINZ
#2: Compost facilities don’t accept PLA
Reality: Some composting facilities accept certified compostable PLA while others do not. The difference often comes down to the processor conditions and cycle timeframes.
Compostability standards define the conditions under which certified compostable products must biodegrade and disintegrate (e.g., temperature, inoculum, humidity). Under EN 13432, for example, packaging must meet specified biodegradation and disintegration requirements, including disintegration testing over 12 weeks and biodegradation testing over a maximum of six months.
Real-world composting facilities may not necessarily operate under the same conditions or timeframes used in compostability testing. In Aotearoa New Zealand, some commercial composting systems operate considerably shorter processing cycles (in some cases around six weeks), or may not consistently achieve the temperatures and other conditions required for PLA to break down within their operating processes.
Research by Scion comparing certified compostable packaging under standardised testing and real-world composting conditions has demonstrated this distinction. Not all industrial facilities reach 55 to 60°C or have cycles of six to nine months. Where the processing conditions or cycle are insufficient for the material to fully disintegrate, residual material may remain at the end of the facility's process. Similarly, where compost facilities meet or exceed standards, the likelihood of residual material derived is minimised or completely avoided.
This does not mean certified PLA is not compostable. It means certification describes how the material performs under defined composting conditions, while facility acceptance depends on whether the real-world process can provide those conditions.
#3: PLA is not compostable
Reality: PLA can be formulated into products that meet recognised compostability standards. Rather than relying on a claim that a product is “compostable”, look for independent third-party certification of the finished product.
Our certified compostable PLA packaging has been independently tested and certified to recognised industrial compostability standards including EN 13432, ASTM D6400 and AS 4736. Certification verifies that the finished packaging meets defined requirements for biodegradation, disintegration and compost quality.
PLA is not a qualifier of compostability. Certification provides the evidence that a particular finished product has met the requirements of the relevant standard.
READ: What does certified compostable mean?
#4: There are no standards for compostability
Reality: While Aotearoa New Zealand does not have its own national compostability standard, there are internationally recognised standards that define how compostable products are tested and certified. These include AS 4736 for industrial composting and AS 5810 for home composting, alongside international standards including EN 13432, ASTM D6400 and ASTM D6868. Independent certification bodies assess products against the applicable standards and issue certification or licences where the requirements are met.
These standards are also recognised in New Zealand Government guidance. The Ministry for the Environment's A guide for selecting compostable products in Aotearoa New Zealand identifies recognised industrial and home compostability standards and certification schemes that can be used to verify product claims. This means compostability is not simply a manufacturer or supplier claim. A certified product should be traceable to the applicable standard, certification body and supporting certification documentation.
Table: A guide for selecting compostable products in Aotearoa, New Zealand. Drafted by The University of Auckland for the Ministry for the Environment.
#5: Bioplastics contaminate compost products with toxic substances
Compostable bioplastics tested and certified according to the European standard for industrial composting EN 13432 (and equivalent standards such as AS 4736, ASTM D6400) are required to disintegrate after 12 weeks and completely biodegrade after six months. That means that 90 per cent or more of the bioplastic material will have been converted to CO2.
The remaining share is converted into water and biomass, which no longer contains any bioplastic. EN 13432 includes toxicity testing (on final products) which determines whether material residuals of composting show any inhibition on plant growth or survival of soil fauna. They also test for PFAS with the universally accepted 100 ppm limit for no intentionally added PFAS.
As a side note, Australia has recognised they need to review their ‘Compost Order’ which helps composters determine inputs because when it was created, plastic contamination was petrochemical, not 100% biobased which are two very different things. A national compost order, like Australia’s, would create the confidence required to scale, accelerating the acceptance of compostables and direct investment into the right infrastructure.
READ: Understanding composability standards: AS 4736 and AS 5810
#6: Bioplastics are taking agricultural land away from food production
Reality: Most bio-based plastics currently use agricultural feedstocks such as corn, sugarcane, beetroot and other carbohydrate-rich crops, so their production does require agricultural land. However, at current production levels, the land requirement is very small relative to global agriculture output. European Bioplastics estimates that approximately 0.624 million hectares, or 0.013% of global agricultural land, is currently used to grow feedstock for bioplastics.
This doesn't make the land use irrelevant. As biobased material production grows, responsible feedstock sourcing and the potential impacts of land-use change remain important considerations. The industry is also developing alternative feedstocks including agricultural and forestry residues, lignocellulosic materials and other waste streams.
At today's scale, however, bioplastics represent a very small share of global agricultural land use.
Where does PLA packaging make sense?
PLA is not a replacement for every conventional plastic application. Its value depends on where it is used and whether an appropriate end-of-life pathway exists.
In foodservice, certified compostable PLA can provide an alternative for takeaway packaging that is difficult to recover through conventional recycling systems, particularly where packaging is contaminated with food.
Where certified compostable PLA packaging; including packaging that utilises PLA as a lining or component, can be collected with food scraps and processed through an industrial composting service, that packaging and its food residue can be managed together as an organic waste stream.
Ecoware supplies corn-based PLA foodservice packaging certified to recognised industrial compostability standards, including ASTM D6400, AS 4736 and EN 13432. Specific certifications vary by product, with supporting documentation available on request.
Want to understand whether PLA is appropriate for your business and available organics pathway? Get in touch with our team at hello@ecoware.co.nz.
