Do polypropylene food containers release nanoplastics into hot water?
Yes. A 2025 study found polypropylene food storage containers released measurable nano- and microplastics, with higher levels after hot-water exposure.
What polypropylene is
Polypropylene, or PP, is the plastic marked with recycling code 5. It is common in reusable food containers, takeout tubs, and some kitchen storage products.
PP is widely used for food contact, but that does not mean heat is irrelevant. Heat can change how much plastic material sheds into water or food.
What the research says
A 2025 study in J Agric Food Chem tested Australian-sourced polypropylene food storage containers under simulated use. The researchers measured nano- and microplastics released into water.
The study found nanoplastic mass concentrations from 0.01 to 3.7 micrograms per liter and microplastic mass concentrations from 0.4 to 10.8 micrograms per liter. Levels were higher after rinsing containers with water at 90 C than at room temperature.
The particles were chemically confirmed as polypropylene. That makes hot plastic food storage a clear exposure point to reduce.
Safer next steps
Do not pour boiling water into plastic food containers. Let leftovers cool before storing them if plastic is your only option. For hot food, soups, and reheating, use glass storage instead.
The research at a glance
| Study | Journal | Year |
|---|---|---|
| Release of Nanoplastics from Polypropylene Food Containers into Hot and Cold Water. | J Agric Food Chem | 2025 |