Storing fatty food in plastic
Major impactFat is the most aggressive extraction medium there is.
The short answer
This is the mechanism people most often miss. Migration depends on how well the migrating substance dissolves in the food, and many plastic additives are lipophilic — they dissolve readily in fat and poorly in water. EU food-contact regulation formalises this by using vegetable oil as the fatty-food simulant in migration testing. Cheese, oil, butter and cured meat in plastic are a harder case than water in plastic.
Why it happens
- Lipophilic additives partition into fat far more readily than into water
- Regulators treat fatty foods as the aggressive test category for exactly this reason
- Storage time is long for staples, so contact is measured in weeks
- Cheese and cured meat have very high film contact per gram eaten
The fix, easiest first
- Glass or steel for cheese, butter, oil and leftovers with sauce
- Ask the deli counter for wax paper rather than a plastic bag
- Buy oil in tin or dark glass, not a plastic squeeze bottle
- Trim and discard the outer surface of vacuum-packed cheese
Packaging this applies to
Plastic film and cling wrap
LDPE, PVC or PVDC film
Plastic squeeze bottle
LDPE or PET, flexible wall
Polypropylene tub
Polypropylene, PP (#5)
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Get my exposure scoreFrequently Asked Questions
Does fat make plastic leach more?
Why does this happen?
What should I do instead?
Sources
- Earth Action with rePurpose Global (2026). Microplastic migration from food and beverage packaging (reported May 2026). Forbes.
- Qian N, Gao X, Lang X, et al. (2024). Rapid single-particle chemical imaging of nanoplastics by SRS microscopy. Proceedings of the National Academy of Sciences (PNAS).
- Winkler A, Santo N, Ortenzi MA, et al. (2022). Does mechanical stress cause microplastic release from plastic water bottles?. Water Research.
- Hernandez LM, Xu EG, Larsson HCE, et al. (2019). Plastic teabags release billions of microparticles and nanoparticles into tea. Environmental Science & Technology.