Compostable Egg Packaging: Reading the Certificate Before the Claim
A European grocery chain began requiring home-compostable certification for egg packaging in 2026. A supplier sent a certificate showing "OK compost INDUSTRIAL" and expected it to pass. It did not: the retailer was asking for home composting, and the industrial certificate only covered an industrial facility at 58 °C — a condition no backyard composter reaches.
Compostability is one of the most misread claims in packaging. The word is used for three different environments, and a certificate for one is not a certificate for another. This guide explains the standards, what they actually test, and how to read a certificate before printing a claim.
Three Composting Environments, Three Different Claims
Industrial composting is a controlled process at 55 to 60 °C with managed aeration and moisture. It breaks material down in weeks.
Home composting is an uncontrolled process at ambient temperature, typically 20 to 30 °C, with variable moisture. It is much slower and much less reliable.
Soil or marine biodegradation are separate environments with their own tests, and a compostability certificate does not cover them.
A product certified for industrial composting is not automatically home compostable, and packaging that says "compostable" without naming the environment is making an incomplete claim.
What the Standards Actually Measure
Compostability certification rests on four requirements, and all four must be met.
Disintegration. The material must break into fragments small enough to pass a defined sieve after a defined time. This is a physical test.
Biodegradation. The material must convert to carbon dioxide, water, and biomass at a rate comparable to a reference material. This is measured by respirometry, usually as a percentage of theoretical CO2 yield.
Ecotoxicity. The compost produced must support plant growth in a defined test. A material that biodegrades but leaves a phytotoxic residue does not pass.
Heavy metals and regulated substances. The material must stay below limits for metals and other restricted inputs.
A certificate that cites only disintegration is not a compostability certificate.
Reading a Certificate Correctly
Five fields matter when a buyer receives a certificate.
| Field | What to look for | Common error |
|---|---|---|
| Standard | EN 13432, ASTM D6400, AS 5810, or a home-compost scheme | Generic "compostable" logo |
| Environment | Industrial or home, stated explicitly | Assuming industrial covers home |
| Product scope | The exact grade and thickness tested | Certificate for a different grade |
| Certificate holder | The manufacturer, and the site | Certificate held by a trader |
| Validity | Current date and surveillance status | Expired or suspended |
The product scope field is where most claims break. A certificate for a 2 mm tray does not cover a 4 mm tray, because thickness changes the disintegration time.
Why Thickness Changes the Result
Biodegradation happens at the surface. A thicker wall has less surface area per unit mass, so it takes longer to break down.
This is why home-compost certification has strict thickness limits for many materials, and why a supplier may hold a certificate for one product but not for the heavier version of the same formulation. Buyers should check the tested thickness against the product they are buying.
Molded Pulp's Position
Molded pulp is fiber-based, and fiber is generally biodegradable. That does not automatically make a molded pulp product certified compostable.
Three things can change the outcome: a water-resistant coating, a wet-strength resin, and a laminated film. Each can slow disintegration or leave a residue above the ecotoxicity limit. A plain molded pulp tray with no coating is a strong candidate; a coated tray needs its own certificate.
For the fiber and coating choices that affect compostability, see the sustainability section, and for how the tray is formed, the transport vibration damage in egg cartons. Certification dossiers regularly trip on inks, and food-contact printing requirements is where that evidence has to come from.
Regulatory Landscape by Market
Compostability claims are regulated differently in each market, and a claim that is legal in one country may be illegal in another.
In the European Union, packaging marketed as compostable must meet the harmonized standard for the application, and several member states restrict compostable packaging to specific uses such as tea bags, coffee pods, and lightweight carrier bags. A claim without a standard reference is exposed.
In the United States, there is no federal compostability standard for packaging. Several states have labeling laws that prohibit the word "compostable" on packaging that does not meet a recognized standard, and California in particular enforces against unqualified claims.
In Australia, AS 5810 defines home compostability and AS 4736 defines industrial, and both are used in retail specification sheets. A supplier citing "Australian standard" without a number has not cited a standard.
The practical implication is that one certificate rarely covers all markets. A brand selling into three markets should map the claims it intends to print against each market's rule before the packaging artwork is finalized, not after.
What to Ask a Supplier
Four questions cut through most of the confusion. Which standard and which environment does the certificate cover? What product grade and thickness were tested? Is the certificate currently valid and in whose name? And what coatings, resins, or inks are present in the product being supplied?
A supplier who can answer all four has a defensible claim. One who sends a logo has sent a marketing asset.
Making a Claim Without Overreaching
If the product is certified for industrial composting only, the claim should say so: "certified industrially compostable" is accurate and defensible. "Home compostable" without a home-compost certificate is not.
Retail buyers increasingly check. A claim that fails a check costs more than a modest, accurate one.
Cost and the Certification Path
Certification is a project, not a purchase. It requires a sample submission, a test period measured in months for home composting, and an ongoing surveillance fee.
The cost is usually justified when a retail customer requires the claim, or when the product is marketed on sustainability. It is not justified for a product sold without a compostability message.
The Bottom Line
Compostability is environment-specific. Read the standard, the environment, the product scope, and the certificate holder before printing anything. Match the tested thickness to the product, and state the environment in the claim. That is the difference between a certification and a liability.
Frequently Asked Questions
Is molded pulp always compostable?
No. Plain fiber is generally biodegradable, but coatings, wet-strength resins, and laminates can prevent certification. Each product needs its own certificate covering its grade and thickness.
Does industrial compost certification cover home composting?
No. They are separate tests at different temperatures and durations. A home-compost claim needs a home-compost certificate such as AS 5810 or an equivalent scheme.
How long does certification take?
Industrial certification typically takes a few months; home composting takes longer because the test runs at ambient temperature. Plan the timeline before committing to a retail claim.