Pregnancy & TTC
Plastic Food Storage: What Actually Matters?
Quick answer
The two things that move the needle most are: don't heat plastic (microwave, dishwasher heat dry), and don't store fatty or acidic foods long-term in plastic. The resin code matters less than how you use it. PP (5) and HDPE (2) are generally the more inert food-contact plastics; PVC (3) and polystyrene (6) are the ones most reviewers suggest avoiding for food.
Our picks
Zero Plastic Rectangular Storage Box 100% Glass
Pyrex
- • Glass base and glass lid
- • Removable silicone seal
Honest caveat: The airtight seal is silicone, which touches food if the box is filled to the brim or stored on its side. Glass lids are heavier and can chip at the edges.
Pyrex
Zero Plastic Set of 3 Storage Dishes with Glass Lids
Pyrex
- • Three glass dishes with glass lids
- • Silicone seals
Honest caveat: Silicone seals sit at the rim. Check sizes before buying: Pyrex sells several Zero Plastic sets at different capacities and prices.
Pyrex
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- Independent certification or lab data for the specific claim.
- Promising research
- The material is well supported, but there is no product-level testing.
- Early research
- Little independent research.
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- Research findings disagree.
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- £20 to £79
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- £80+
What the resin number on the bottom means
- 1 PET - drink bottles. Single-use by design. Don't refill or heat.
- 2 HDPE - milk jugs, some food tubs. Considered inert for food contact.
- 3 PVC - cling film historically, some bottles. Phthalate plasticisers are the main concern.
- 4 LDPE - bread bags, some squeeze bottles. Generally considered inert.
- 5 PP (polypropylene) - most modern food tubs, yoghurt pots, Tupperware. Heat-tolerant up to ~100°C, considered one of the more inert food plastics.
- 6 PS (polystyrene) - takeaway containers, disposable cups. Styrene migration is a concern especially with hot or fatty foods.
- 7 Other - mixed. Includes polycarbonate (historically the main BPA source) and increasingly bio-plastics.
The behaviours that actually move risk
The clearest, most-cited evidence is around heating plastic and around fat or acid contact over long periods. Both increase migration of plasticisers and unreacted monomers into food. That holds even for plastics labelled food-safe at room temperature.
A reasonable everyday rule: room temperature storage in PP (5) or HDPE (2) tubs is fine; reheating, microwaving, or storing oily leftovers in plastic is where most reviewers and regulators suggest switching to glass or stainless.
'BPA-free' alone isn't the answer
BPA replacements (BPS, BPF) have been found to have similar endocrine activity in animal studies. 'BPA-free' on a label is reassuring but not the whole story. The structural fix is using plastics that don't need bisphenols in the first place (PP, HDPE) or moving to glass and stainless for the use cases where it matters most.
Where it's reasonable to keep plastic
- Dry goods (rice, pasta, nuts) at room temperature.
- Cold leftovers eaten within a day or two.
- Anything that won't be heated or stored long-term with oil or acid.
Where it's worth switching to glass or stainless
- Anything you reheat in the container.
- Fatty foods (curries, oily leftovers) stored more than a day.
- Acidic foods (tomato sauce, citrus) stored more than a day.
- Children's everyday food (precautionary, not because the evidence shows acute risk).
Frequently asked questions
Is it OK to microwave a container labelled 'microwave safe'?
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It means the plastic won't deform at microwave temperatures, not that nothing migrates. Independent testing has repeatedly found measurable migration of plasticisers and antioxidants during microwaving, even from compliant containers. Glass is the simpler choice if you're heating.
Which plastic numbers are best for food?
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5 (PP) and 2 (HDPE) are widely considered the more inert options. Avoid 3 (PVC), 6 (PS) and unspecified 7 for food contact.
Are BPA-free containers fine?
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They've removed BPA but most use BPS or BPF, which animal studies suggest behave similarly. 'BPA-free' is an improvement on bisphenol-containing plastic, not a green light for unlimited use.
Last updated
Sources
- EFSA scientific opinion on BPA
- FDA food-contact substance database
- Environmental Working Group plastics guidance
- Endocrine Society scientific statements on bisphenols