Does Slow cooker liner have microplastics?
The short answer
The longest hot polymer contact in this entire database. A nylon bag holds your food at 90–100°C for six to eight hours, and nylon is the polymer that released billions of particles from a tea bag in fifteen minutes of the same treatment.
Flexible pouch or laminate sachet format profile
Why Slow cooker liner scores 71
Six to eight hours at simmering temperature — no other product in the database sustains hot contact for that long
Nylon is the same polymer family measured releasing billions of particles from a mesh tea bag at 95°C
The bag touches every surface of the food, and slow-cooker food is usually fatty and often acidic
It is sold specifically to avoid washing the pot, which means the alternative is free
Where the 71 comes from
Five components, added. The page renders the parts rather than a stored total, so the number cannot disagree with the reasoning behind it.
- Packaging contact
- 26 / 30
- Use conditions
- 25 / 25
- Measured release
- 12 / 25
- Polymer behaviour
- 8 / 10
- Processing
- 0 / 10
What material touches the contents, over how much surface area, for how long. Glass and steel score near zero here; a film pressed against fatty food scores near the top.
Heat, abrasion, flexing, repeated opening, reuse beyond design life. The same bottle scores differently in a fridge and in a hot car.
What a laboratory actually counted, for this product or its category. A high number here means real particles were measured, not that the material looks suspicious.
How this specific polymer behaves — brittleness, fat solubility of its additives, thermal stability, whether it is a polymer named in existing restrictions.
What happened before you bought it. Retort sterilisation inside the pack, hot-filling, and pressurised brewing all happen at the most migration-favourable moment.
What we don't know
Nobody has measured a slow cooker liner. The Hernandez tea-bag result establishes that nylon sheds heavily into hot water; a liner is a thicker film at a lower temperature for a much longer time, and how those trade off has not been studied. The direction is not in doubt and the magnitude is genuinely unknown.
This section is on every page in the database, including the ones where the answer is comfortable. How evidence grades work →
Better options
Ordered by how much they change, not by how much they cost.
No liner — the ceramic pot is the point
soak it for ten minutes and it washes out
A slow-cooker-safe glass or ceramic insert
if the goal is portioning rather than washing up
Cook in a Dutch oven instead
enamelled cast iron, no liner conceivable
Check the one in your kitchen
This page scores Slow cooker liner as a product. Formulations, packaging and suppliers change, and the specific item you own has its own condition — a scratched pan and a new one are not the same object. Scan yours for a score built from what is actually in front of you.
Scan my cookware & prepSources behind this score
Each with the finding we use it for and the limitation that finding carries — because a study quoted without its boundaries is how this subject got so noisy.
- peer-reviewed2019
Hernandez 2019 (McGill) — A single nylon or PET pyramid tea bag steeped at 95°C released about 11.6 billion microplastic and 3.1 billion nanoplastic particles into one cup.
Limitation: Four commercial bags, brewed empty of tea leaves to avoid interference. The particle count is enormous but the total mass is small, and the study measured release into water, not what happens after you drink it.
- peer-reviewed2023
Hussain 2023 (Nebraska) — Three minutes of microwaving released up to 4.22 million microplastic and 2.11 billion nanoplastic particles per square centimetre of container surface.
Limitation: Polypropylene and polyethylene containers with water and acetic acid, not real food. The headline figure is the worst case in the study, per cm², not per meal.
- report2026
Earth Action 2026 — Estimated roughly 1,000 tonnes of microplastics migrate from packaging into food and drink annually — about 130 mg per person per year — with PET bottles responsible for around a third, and found UV exposure can raise release up to 100×.
Limitation: An industry-funded modelling exercise, not a laboratory study, and not peer-reviewed. We use it for the relative ranking of formats rather than for any absolute number.
Frequently Asked Questions
Does Slow cooker liner have microplastics?
How was the Slow cooker liner score of 71 calculated?
Is Slow cooker liner safe?
Why is the confidence only 60%?
Scored next to this
Pyramid mesh tea bag
Nylon or PET mesh
Grade A · 90%
Microwave rice pouch
Multi-layer plastic pouch, heated with the rice inside it
Grade B · 76%
Microwave ready-meal tray
CPET or polypropylene tray with a film lid
Grade B · 78%
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