This article was translated from Italian by ChatGPT
For years, we have been asking ourselves which material should replace the old plastic shopping bag.
But perhaps we have been asking the wrong question.
Do we really need a new bag every single time we carry our groceries home from the supermarket?
On the one hand, we have the single-use shopping bag, now often made from biodegradable and compostable bioplastics. In certain applications, this certainly represents progress compared with conventional plastic, but it remains an object manufactured to have a very short lifespan.
On the other hand, there is something much simpler:
a strong string, mesh or fabric bag that can be reused hundreds of times.
The European Commission sets out a very clear hierarchy: biodegradable and compostable plastics should primarily be used where reducing, reusing or recycling is not possible.
Moreover, “compostable” does not automatically mean biodegradable in every environment: the conditions and timeframe matter.
AND WHAT ABOUT PHA?
This is where the discussion becomes even more interesting.
PHA (polyhydroxyalkanoates) belong to a different family of biopolymers, produced biologically by microorganisms.
Some PHAs can biodegrade in different environments, depending on their formulation and the surrounding conditions.
But they do not answer the simplest question:
Why produce a new bag when we can reuse the one we already have?
PHA becomes particularly interesting when single-use products are genuinely necessary, and especially in applications where there is a risk that the material may escape waste collection and end up in the environment.
THREE QUESTIONS, IN THIS ORDER
1. CAN I AVOID IT?
Use a string or fabric bag for years.
2. DO I REALLY NEED TO PRODUCE A SINGLE-USE ITEM?
If so, choose the material according to its actual end-of-life pathway.
3. COULD IT END UP IN THE ENVIRONMENT?
If so, biodegradation under the actual conditions of the intended environment becomes a fundamental characteristic.
AN APPEAL TO SUPERMARKETS: LET’S STOP DISTRIBUTING SINGLE-USE SHOPPING BAGS
Perhaps the time has come to go one step further.
We are calling on supermarkets to progressively stop distributing single-use shopping bags at checkouts, even when those bags are biodegradable or compostable.
Not because these materials have no purpose. They do, and in some applications their role is important.
But a bag that is manufactured, transported, used for a few minutes and then discarded remains a single-use object.
Why not encourage an extremely simple alternative instead?
A string, mesh or fabric bag. Strong, washable and attractive.
One that can be used a hundred, five hundred, perhaps even a thousand times.
A supermarket could sell it to us once instead of continuously selling us new bags.
And we, as consumers, should learn to bring it with us.
For applications where single use really is unavoidable, we should continue improving materials.
And where there is a genuine risk of leakage into the environment, we should study biopolymers such as PHA, assessing their biodegradation under the real conditions of their intended destination.
But to carry our groceries home, perhaps we do not need to invent yet another bag.
We simply need to stop throwing one away every time.
BRING YOUR OWN BAG FROM HOME.
Fewer shopping bags. More reuse. PHA where single use is genuinely necessary.
True sustainability is not only about producing better waste.
First and foremost, it is about not producing that waste at all.
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LA BORSA PIÙ ECOLOGICA?
— MARCO ASTORRI (@astorrix) September 6, 2026
FORSE È QUELLA CHE NON BUTTIAMO MAI
Per anni ci siamo chiesti con quale materiale sostituire la vecchia shopping bag di plastica.
Ma forse la domanda è sbagliata.
Per portare la spesa dal supermercato a casa abbiamo davvero bisogno, ogni volta, di una… pic.twitter.com/JFl8nh5mh9