Is it safer to thaw breast milk in the fridge or warm water?
Fridge. Slow thaw in glass keeps plasticizers out of the milk.
What's actually in it
Breast milk thawed in warm water (inside a plastic storage bag) creates a warm, fatty environment against plastic. That's the classic setup for maximum migration of plasticizers and microplastic particles.
Fridge thawing takes longer but holds the milk below 4°C, which dramatically slows chemical migration.
What the research says
A 2025 study in J Agric Food Chem measured particle release from common food contact plastics at hot and cold temperatures. Cold water released a small fraction of what hot water did.
Thaw frozen milk in the fridge overnight. For faster thaws, transfer to a glass bottle first, then warm by running lukewarm water over the glass, not the plastic bag.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| Release of Nanoplastics from Polypropylene Food Containers. | J Agric Food Chem | 2025 |
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