A buyer committing to a compostable food packaging program should require written disclosure of the exact polymer or fiber substrate, the certification scope (which standard, which certificate number, which issuing body, and whether it covers the finished SKU or only a resin or sheet input), and a finished-SKU specification sheet covering dimensions, wall or gauge, closure type, and intended use conditions. The direct answer is that no program should move to purchase order until those three layers — material identity, certificate scope, and finished-SKU data — are documented in writing and matched against the item the supplier will actually ship.
Why material identity is the first gate
Compostable is a category term, not a material. Substrates in commercial use include polylactic acid (PLA), polybutylene adipate terephthalate (PBAT) blends, starch-based compounds, molded fiber, and coated paperboard. Each has different heat tolerance, moisture behavior, and end-of-life pathway. Two suppliers can both describe a product as compostable while offering different polymers with different processing behavior, which affects how a container performs in a hot-fill or microwave application, how it stacks, and how it behaves in cold storage.
A written disclosure should name the base polymer or fiber, any additives, the coating or lining if present, and the colorant system. If the answer is a blend, ask for the blend ratio range. If the answer is coated paperboard, ask what the coating is and whether it is designed to break down under the intended disposal condition.
Certificate scope: the most common gap
A certificate that covers a resin pellet is not the same as a certificate that covers the finished cup, lid, or clamshell. Buyers should verify four things in writing:
- the exact standard the certificate is issued against, cited by name and year;
- the certificate number and the issuing body, so it can be checked independently;
- the scope statement — does it list the finished product, the model, or only an input material;
- the expiry or review date, and whether the scope is limited to a specific manufacturing site.
If the scope is limited to an input material, the buyer should ask what additional documentation covers the finished article, and whether conversion, printing, adhesive, or coating steps could affect the claim. This is a documentation question, not a legal conclusion; the buyer's own compliance team should determine what the program requires in the destination market.
Finished-SKU disclosure before commitment
Once material and certificate scope are clear, the finished-SKU layer decides whether the program is workable. Request a specification sheet that states:
- product type and closure format, including whether the lid is hinged, separate, or a film seal;
- nominal capacity and fill guidance, expressed in the units your operation actually uses;
- dimensions and wall or gauge ranges, with the method used to measure them;
- temperature and storage guidance supplied by the manufacturer for that specific SKU;
- whether the item is intended for single use, and any reuse guidance the manufacturer provides;
- the exact model designation, so reorders can be matched to the same article.
For molded fiber and paperboard items, dimensional tolerance tends to be wider than for injection-molded PP, and the buyer should ask how the supplier controls that variation lot to lot. For compostable cups and containers used with lids, the closure fit is a separate specification: a lid verified for one substrate may not be verified for another.
Disposal reality should be part of the specification
A compostable item only delivers its intended end-of-life benefit where a collection and processing pathway exists. The buyer's specification should state the intended disposal route — industrial composting, home composting, or another pathway — and the supplier should confirm in writing whether the submitted documentation supports that route for the finished SKU. Where the destination market lacks the relevant infrastructure, the program may still be viable as a material choice, but the buyer should document that the end-of-life claim depends on local conditions rather than on the packaging alone. Buyers who want more background on this can review the disposal-infrastructure discussion and the compostable vs PP comparison.
How to verify a supplier's disclosure package
Use a staged method rather than a single trust decision:
- Ask each shortlisted supplier for the three-layer disclosure in writing: material identity, certificate scope, finished-SKU specification.
- Compare the documents against the actual sample. Check that the sample label, model designation, and material statement match the paperwork.
- Verify the certificate independently with the issuing body where the body offers a public register.
- Ask which production site will run the order and whether the certificate scope names that site.
- Confirm what happens if the material or site changes after approval — request a change-notification commitment in the order terms.
- Retain the approved specification and a sealed reference sample for each SKU so incoming lots can be compared.
This method does not require the buyer to accept any performance claim on faith. It requires the supplier to put specifics in writing so the buyer can check them.
What to put in the inquiry
A useful first inquiry names the item type, the intended food contact use, the closure format, the expected capacity range, the disposal pathway you are targeting, and the market where the product will be sold. Ask the supplier to return the material identity, certificate scope, and finished-SKU specification together, and to state clearly which parts of the program are subject to project-specific verification. Suppliers with existing mould programs can usually indicate available sizes and closure formats quickly; new shapes or capacities typically require a separate development step.
JR DELIPACK's compostable material programs are a project capability, and the exact material, certification scope, and finished-SKU claims are verified per order rather than assumed from a family-level description. Buyers can start from the compostable food packaging programs page and send the three-layer disclosure request through the contact page.
FAQs
Can a supplier send a certificate that covers only the raw material?
Yes, and this is common. The buyer should treat it as partial evidence and ask separately what documentation covers the finished article, including any converting, printing, or coating steps.
Does a compostable label guarantee the item will be composted?
No. The end-of-life outcome depends on collection and processing infrastructure in the market where the item is discarded. The certificate describes the material's tested behavior under defined conditions, not the local waste system.
What if the supplier cannot state a temperature range for the SKU?
Ask for the manufacturer's guidance for that specific model in writing. If it is not available, the buyer should not fill that gap with assumptions, and should treat the specification as incomplete.
How do I compare two compostable suppliers fairly?
Request the same three-layer disclosure from both, compare certificate scope statements line by line, and check whether each finished SKU has its own specification sheet rather than a family-level description.
Should the disposal pathway be written into the specification?
It should be stated, because it defines which documentation the buyer needs. Whether the buyer can make an end-of-life claim in a given market is a decision for the buyer's own compliance review.