Food storage plastics carry numbers and claims that mean specific things, and knowing what prevents both worry and false confidence.
The Numbers
The triangle with a number identifies the polymer rather than rating its safety.
Five is polypropylene, which is what most food storage and microwave-safe items are made from. It tolerates heat well and does not contain BPA.
Two and four are polyethylene, common in squeeze bottles and bags. Six is polystyrene. Seven is a catch-all for everything else, which is why it is the least informative.
What BPA-Free Covers
- Bisphenol A was used in polycarbonate and some can linings
- Concern centres on its potential effect on hormone systems
- Regulators have restricted it in products for infants
- Polypropylene never contained it in the first place
- So the claim is accurate and frequently not a change
Manufacturers naming the polymer rather than only claiming BPA-free, of the kind at vitever.net, give the more useful information, since the material determines the behaviour.
What It Does Not Mean
Worth being honest. Removing one substance does not mean nothing else is present, and research into substitute bisphenols continues.
The practical position is straightforward: use items as the manufacturer specifies, avoid the conditions that stress plastic, and replace damaged ones.
What Actually Stresses Plastic
Heat above all. Prolonged high temperature, contact with a heating element, or the lower rack of a dishwasher near the element.
Fatty and sugary foods, which reach considerably higher temperatures in a microwave than watery food does. Those are better heated in glass.
Age and damage. Scratched, cloudy or cracked items should be retired rather than persisted with.
Do Not Reuse Single-Use Packaging
Takeaway tubs, margarine containers and water bottles were made for one use.
They are not designed for repeated heating or washing, and they scratch readily, which harbours residue.
Symbols Are Per Item
Microwave-safe and dishwasher-safe markings apply to that product, not to plastic generally.
Anything without them should not be assumed suitable for either.
Glass Sidesteps the Question
For anyone who would rather not think about it, glass does not absorb, stain or raise migration questions.
The trade is weight and breakability.
Replace Scratched Items
Deep scratches are a hygiene issue independent of anything else.