What does certified compostable mean?
Certified compostable means a product is third-party verified confirming it will completely biodegrade in industrial or home composting environments into CO2, water, and biomass with no toxic residues or persistent fragments in finished compost. In this article we will look at what defines certified compostable, the standards that certification bodies test to verify compostability and why certification is important.
While the American standard ASTM D6400 was developed in 1999, Europe’s EN 13432 (released in 2000) is the legal and technical blueprint for the modern world. EN 13432 was so thorough that subsequent international guidelines, including ISO standards, were modelled directly after its strict framework. The European standard EN 13432 defines the minimum requirements packaging has to meet in order to be processed by industrial composting. The objective of the EN 13432 standard is to increase food waste diversion by certifying that packaging and bags can safely break down in industrial composting alongside food scraps. This removes the need to separate food from its packaging and people recycle more food when it is convenient.
What is compostable?
A compostable product is one that can biodegrade in a specific composting environment, typically within a defined time frame and under specific conditions. The term ‘biodegradable’ is widely used and misunderstood since almost all materials biodegrade eventually. Without clear conditions, timeframes, or standards, the claim alone is meaningless and misleading. This is why certification to recognised compostability standards is important.
Independent certification provides assurance to composters that a finished product — including inks, coatings, labels, adhesives, and additives will safely break down under defined composting conditions without leaving harmful residues.
Compostability is verified by independent third-party certification bodies against either industrial or home composting standards. The most recognised certification bodies globally include:
* TÜV Austria
* DIN CERTCO
* Biodegradable Products Institute (BPI)
* Australasian Bioplastics Association (ABA)
Composting in practice: Manurewa High School x Green Gorilla
The EN 13432:2000 Standard
The criteria for industrial compostability are set out in the European standard EN 13432, which requires the compostable product to:
1) disintegrate after 12 weeks, and
2) completely biodegrade after six months*
*90% or more of the material is converted to CO2, and the remaining is converted into water and biomass – i.e. valuable compost.
EN 13432 is the reference standard for all certification bodies. The European Norm about compostability of packaging (EN 13432) requires packaging to pass four key tests:
Biodegradation: chemical breakdown by microorganisms
Disintegration: physical breakdown into fragments small enough to pass compost screening
Eco-toxicity: verification that resulting compost does not inhibit plant growth
Heavy metal content: ensuring contaminants remain within safe limits
The Australian industrial composting standard AS 4736 includes these requirements and adds an additional earthworm toxicity test, providing further assurance of compost safety.
Home compostability standards
TÜV AUSTRIA developed OK compost HOME to guarantee 100% biodegradability in a garden compost. This certification forms the basis of AS 5810, the Australian Standard for Home Composting. To achieve home compostable certification, a product must:
1) 100% biodegrade into completely non-toxic by-products
2) disintegrate within 180 days. Not more than 10% of the original dry weight present in a > 2mm screen fraction
3) achieve ultimate biodegradability (90% absolute biodegradation) within 12 months.
READ MORE: Why isn't certified compostable packaging accepted in kerbside FOGO collections?
Are all compostable products accepted in compost collections?
While compostability standards define how materials behave under controlled test conditions, real-world outcomes depend entirely on commercial infrastructure, temperature consistency, contamination risks, and composter acceptance. To deliver actual environmental benefits, packaging must align with existing local processing capabilities.
With specialised waste contractors now diverting tonnes of food scraps and compostables from landfill, businesses and consumers must understand exactly what can and cannot be accepted in the organic stream.
If you’re a business adopting compostable packaging or already using it and need help connecting your site(s) with a local compost collection partner, we’re happy to help. Get in touch at hello@ecoware.co.nz.
If you are assessing your packaging supply and would like help interpreting certifications to ensure conformity to venue or contractor requirements, we can also assist.
