A guide to safe plastics

By Efrosini Costa

A guide to safe plastics
A little food-storage-know-how goes a long way to finding the safest plastic for the job.

The latest scientific research has given us lots of important reasons to think carefully about how we use plastics. But with so many different shapes, sizes and types on the market it’s hard to know which is the best plastic for the job.

When it comes to deciphering plastic containers it’s all a matter of numbers.  By looking at the number and chasing-arrows symbol stamped at the bottom of your container – often disregarded as a recycling symbol – you can differentiate between the, the bad and the ugly.

Polypropylene (PP, #5) – A relatively high melting point makes this plastic, often used in a disposable capacity, a safer alternative for warm or cold foods. While many of these plastics undergo testing for prolonged use, they may break down faster than your durable plastic tupperware, so only use them for as long as recommended by the manufacturer or no more than 5-6 times.

High-density polyethylene (HDPE, #2) or polypropylene (PP, #5) – Designed to store food at cooler temperatures for a limited time – think yoghurt, milk, cheese – these containers are likely to melt when subject to heat. Reuse them only for cold food storage and be sure to recycle them once they show signs of wear and tear – such as warping, scratches and discoloration.

Polyvinyl chloride (PVC or V, #3) or low-density polyethylene (LDPE, #4) – Not all cling-wraps are created equal. Choose those that are made from LDPE as PVC contains vinyl chloride – a known human carcinogen. If you buy meat or cheese wrapped in plastic remove as soon as possible and store in a glass or ceramic container. Try tempered glass for freezing and parchment paper for shorter periods of time. Never put cling-wrap or zippered bags in contact with hot food and liquid as this can cause them to melt and release chemicals.

Low-density polyethylene (LDPE, #4), polypropylene (PP, #5), or polycarbonate (PC, #7) – For durable everyday use, opt for containers marked with #4 or #5. Those marked #7 are known to leach low levels of an estrogen imitator that can cause serious health risks for women. Note that #7 is a ‘catch-all other category’ that means it can be hard to discern the good from the bad – avoid them all together. Many of these options are dishwasher and microwave safe but always check the labels. Avoid microwaving foods with a high-sugar content – like sauces and sweets – which reach higher temperatures when warmed up, making them more likely to melt plastic.

Polypropylene (PP, #5) or polystyrene (PS, #6) – Used for takeout these containers don’t appear to leach chemicals, but as they are intended for one-time usage they are not subject to scrutiny or testing – so don’t use them for storage. Polystyrene, otherwise known as ‘styrofoam’ can be found in a clear, hard form. Be careful as both are made with bezene and can leach styrene – a well-known hormone disrupter and possible human carcinogen. Don’t reheat food in these containers unless you see a “microwave-safe” symbol on the bottom.

Remember; when in doubt always read the label or check the manufacturers instructions. Alternatively there are some great new products on the market now for ceramic, glass and metal containers and canisters for storing food and drink in.


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