CPLA vs. PSM cutlery. How green are they & which is better?

Looking for eco-friendly cutlery for takeaway food? You may have come across some of the widely available options. Cutlery made from sustainably sourced wood is a fantastic green choice. And, CPLA bioplastic cutlery is popular with those who prefer the texture and feel of, well, bioplastic. There are also outlets selling PSM cutlery, which is cheaper than CPLA and often described as biodegradable and plant-based. But what are CPLA and PSM utensils made from? And how sustainable is each of these materials? Here is our CPLA vs. PSM cutlery comparison.

Raw Materials

CPLA is crystallised PLA (polylactic acid), a compostable bioplastic made from plant starch (frequently industrial grade corn). PLA is heat sensitive above 40 °C, but crystallising it increases its heat resistance to around 95 °, while it remains fully compostable.
(The terms PLA and CPLA are somewhat interchangeable, basically referring to the same material. You may see this cutlery referred to as PLA cutlery, too. One key difference, however is that CPLA is opaque, while PLA can be clear.)
CPLA (and PLA) is a fully plant-based material and 100% renewable.

PSM stands for ‘plant starch material’. However, PSM cutlery is not fully renewable and plant-based, but a hybrid material – a blend of plant based bioplastic resin and petroleum-based plastic. This creates a plastic with a high tolerance for heat.
There is no standard ratio of plant-based content to fossil fuel-based content, and the cutlery could be anywhere from 20% to 70% plant-based.

End of Life

CPLA is biodegradable and certified compostable. It requires large-scale or industrial composting conditions to biodegrade quickly. In a large compost pile it will break down into harmless biomass within 180 days (usually much quicker – in good conditions it can break down within less than two weeks). As a product that is certified compostable, CPLA has been tested according to international standards. So you can rest assured it is genuinely compostable and can biodegrade into healthy biomass.

PSM is not compostable. We have seen some companies claim that PSM cutlery is biodegradable. Unless these claims have certification to back them up, they are unreliable at best and potentially very misleading. (From our standpoint, we don’t believe we have yet come across genuinely biodegradable or compostable cutlery in South Africa that is made from a blend of plant starch and petroleum plastic.)

Companies selling PSM often claim that it will break down in landfill in a certain amount of time. Again, this seems misleading as landfills are not designed to break anything down. Waste is compacted and includes a lot of suffocating plastic with very limited oxygen.

While the use of plant-based materials is a good thing (they are renewable with a lower carbon footprint), mixing them with plastic and creating a non-compostable product means the cutlery is destined to become waste.
Also, as PSM does not undergo compostability certification, it is not tested to ensure that it adheres to international eco-toxicity standards.

CPLA vs. PSM Cutlery

CPLA vs. PSM Cutlery: Our Verdict

CPLA is 100% plant-based and renewable and fully compostable. It provides excellent functionality, with a viable end-of-life solution. It thus offers a significant upgrade when compared to conventional petroleum-based plastic.
CPLA does need to be composted in large-scale composting facilities, however. While the composting sector is growing (in South Africa and globally), we would like to see this growth speed up significantly, so that we can divert more food waste, together with compostable packaging, from landfill.

PSM is non-compostable and therefore functionally the same as plastic cutlery. Therefore, we don’t think it can be considered a viable sustainable option. Does it make sense to mix biodegradable plant-materials with petroleum plastic to make more non-compostable plastic? We don’t think so.
PSM has no end-of life strategy and is destined to become waste. Designing products for landfill only leads to increased pollution.

We have unfortunately been seeing misleading claims about cheaper, non-compostable ‘bioplastic’ products for a long time. Have you heard about the burn test? It’s one way to test if your cutlery is genuinely compostable.

By only designing and supporting products that fit into a circular economy we can aid our transition towards a waste-free society.