Last updated: 14 September 2026.
Quick answer: A recycled bottle’s material passes through six stages — collection, sorting, baling, washing into flake, pelletising, and (for food contact) decontamination. Traceability is lost most often at the seams between stages: when a bale changes hands, when flake is blended, when a trader consolidates loads. A brand that wants a defensible recycled-content story should know which stage its supplier buys from, and which certificate exists at each one. “We buy recycled resin” is not a supply chain description.
Where this fits: This is the upstream story behind the PCR cosmetic bottles guide, which covers certification and limits. Read this page when you need to explain — to a retailer, an auditor or your own board — where the recycled content physically comes from.
The six stages
Every post-consumer recycled pellet has travelled this route, whether or not anybody documented it.
Stage 1 — Collection
Material enters the system either through kerbside collection (mixed recyclables in a household bin, commingled with glass, metals, paper and other plastics) or through a deposit return scheme (DRS), where consumers pay a small deposit and return the container to a reverse-vending point.
The difference in material quality is substantial. DRS streams are dominated by beverage containers — a narrow, clean, high-value feedstock. Kerbside streams are broad and variable, which is why food-grade recycled PET is so often built on DRS-sourced material and why regions without a DRS find it harder to supply bottle-to-bottle recycled content.
Stage 2 — Sorting
At a materials recovery facility, mixed material is separated. Plastics are identified largely by near-infrared (NIR) sorting, which reads the polymer type optically and can be configured to reject specific colours or to separate by grade. Manual pre-sorting removes gross contamination; magnets and eddy currents pull metals; air classifiers and screens handle the rest.
Sorting efficiency is where the recycled-content ceiling on a region actually lives. If the NIR line cannot cleanly separate PET from PETG, or cannot remove PVC, the resulting flake carries contamination that no later stage fully removes.
Stage 3 — Baling
Sorted plastic is compressed into bales for transport. A bale is the first tradable unit in the chain — and the first place traceability weakens, because bales are bought, sold and consolidated by traders who are not necessarily part of any certification scheme.
Stage 4 — Washing into flake
At the recycler, bales are opened, shredded and washed. Float-sink separation exploits density differences to split polymer types; hot washing with a caustic solution removes product residue, adhesives and surface contamination; rinsing and drying prepare the material for melting.
This stage does most of the work on physical cleanliness — and, as we describe in our article on why PCR smells, most of the work on odour too. It is also the stage most sensitive to operator practice, which is why recycler-level auditing matters more than a polymer declaration.
Stage 5 — Pelletising
Washed flake is melted, filtered and extruded into pellets. Filtration removes residual solid contaminants down to a defined micron rating; the extrusion conditions set the thermal history of the material. From here the output is a tradable commodity — the point at which most converters enter the chain.
Stage 6 — Decontamination for food contact
For material destined to touch food or drink, there is a further requirement: the recycling process itself must be capable of removing any potential contaminants that migrated into the plastic from its previous contents. This is achieved through super-clean decontamination — typically extended high-temperature processing under vacuum or inert gas, or solid-state polycondensation for PET — carried out under a validated, authorised process rather than a generic extrusion line.
This is the stage that turns “recycled pellet” into “food-grade recycled pellet”, and it is the stage brands most often assume has happened when it has not.
Where traceability breaks
| Stage | What happens | Where traceability is at risk | Document that should exist |
|---|---|---|---|
| 1 Collection | Kerbside or DRS | Origin is aggregated; individual containers anonymised | Scheme or municipal records |
| 2 Sorting | NIR, manual, metal removal | Output quality varies by shift and line configuration | MRF output specification |
| 3 Baling | Compression, trading | Bales change hands; consolidation mixes sources | Bale specification, trader records |
| 4 Washing | Shred, float-sink, hot wash, dry | Operator-dependent cleanliness and odour | Recycler audit / traceability certificate |
| 5 Pelletising | Melt, filter, extrude | Blending of lots during extrusion | Batch records, filtration rating |
| 6 Decontamination | Validated super-clean process | Only specific authorised processes qualify | Process authorisation, per-lot test data |
The pattern to notice: the weakest links are commercial, not technical. Bales and flake are traded commodities, and each trade is an opportunity for provenance to be documented loosely or not at all. A chain-of-custody system exists to close exactly that gap.
Bottle-to-bottle vs bottle-to-fibre
The same collected bottle can end up in two very different places, and the economics explain a lot about recycled-content pricing.
- Bottle-to-bottle keeps the material inside the packaging loop: collection → food-grade decontamination → new bottle. It demands the cleanest feedstock, the most validated processing and the strictest documentation, which is why bottle-to-bottle rPET typically commands the highest value in the recycled plastics market.
- Bottle-to-fibre downgrades the material into polyester fibre for textiles, which tolerates more contamination and does not require food-contact validation. It is a legitimate and important recycling route, but it is not a closed loop — the fibre usually has no route back into packaging.
For a brand making a circularity claim, the distinction matters: buying fibre-grade recycled content does not close your own packaging loop. If your claim says “bottle back to bottle”, the chain must actually include stage 6.
Food contact: what makes recycled plastic legal in the EU and the US
Two regulatory routes carry the weight for recycled plastic in contact with food.
European Union. Recycled plastic for food contact is regulated under Regulation (EU) 2022/1616, which replaced the earlier framework. Its central requirement is that the recycling process itself must be authorised — a technology, not just a facility, and the process must be able to demonstrate that it reduces contamination to a level that protects consumers. Materials may only be placed on the market where the process complies, and the framework includes monitoring and declaration obligations along the chain. The resin must additionally satisfy the general food-contact requirements that apply to all plastic materials, including the migration framework that cosmetic and personal-care packaging buyers will already recognise from EU 10/2011.
United States. The Food and Drug Administration evaluates recycling processes and issues a no-objection letter (NOL) where the process is found capable of producing material suitable for food contact under the intended conditions. Buyers should expect the NOL to name the process owner — the recycler — rather than the brand or the converter, and to specify the feedstock and use conditions it covers.
The practical consequence for a packaging buyer is the same on both sides of the Atlantic: ask for the authorisation behind the resin, not for a statement that the resin is “food grade.” It is the process that is authorised, and it is issued to a specific party for a specific scope.
What to ask before you accept a recycling claim
- Which stage does my supplier buy from? Resin from a validated decontamination line and flake from an unknown wash line are not the same purchase.
- Which recycler, and are they independently audited? Recycler-level traceability schemes exist precisely to make this answerable.
- Is there a transaction certificate for this order? Scope-level certification tells you a facility is capable; a transaction certificate ties a shipment to recycled input — the distinction is set out in our mass balance explainer.
- For food contact, who holds the process authorisation or NOL, and what does it cover? Feedstock, use conditions and process owner all matter.
- Can the chain be evidenced from bale to pellet? Not “we are certified”, but “here is the documentation trail for this material.”
Frequently asked questions
Why is food-grade recycled PET so much more expensive?
Because it carries the full cost of the chain: clean feedstock (usually from deposit systems), rigorous sorting, thorough washing, and a validated decontamination process with per-lot test data. You are paying for the documentation as much as for the polymer.
Can any recycler produce food-grade recycled pellet?
No. The decontamination step has to be a validated process capable of removing contamination from previous contents, and in the EU the process itself must be authorised. A standard extrusion line is not a substitute.
What is a deposit return scheme and why does it matter to packaging buyers?
It is a system where consumers pay a refundable deposit on a container and return it for recycling. Because the returned material is dominantly beverage containers, the stream is narrow and clean — which is why it underpins bottle-to-bottle recycled content in the markets that operate one.
Does recycling plastic mean it is truly circular?
Only if the material returns to the same application class. Bottle-to-bottle closes the loop; bottle-to-fibre is recovery rather than circularity for packaging, because the fibre does not come back as a bottle.
What is chemical recycling, and does it count?
Chemical recycling breaks polymers down to monomers or feedstock rather than mechanically reprocessing them. It can handle streams that mechanical recycling cannot and can in principle return material to food-contact quality, but it is a different technology with its own authorisation status and its own place in recycled-content accounting. It should be described as what it is, not folded silently into a mechanical-recycling claim.
How much of the chain can a bottle manufacturer actually control?
The converter controls stages 5 and 6 where it owns them, and selects its resin supplier for stages 1 to 4. That is why the meaningful question for a brand is not whether the converter is certified, but which upstream partners it buys from and what documentation those partners provide per delivery.
Shijin Packaging — factory-direct cosmetic and daily-chemical plastic bottles since 2003, operating 30+ automatic blow-moulding lines and 10+ injection-moulding machines across a 15,000 m² facility in Huizhou, Guangdong, with daily capacity of approximately 200,000 pieces; GRS-certified PCR bottles with per-batch chain-of-custody documentation.
- Website: https://shijinpackaging.com
- Full catalogue: https://shijinpackaging.com/catalog/
- Email: sales@shijinpackaging.com