Polylactic acid (PLA) is one of the most widely used bioplastics in compostable food packaging. Derived from plant-based sugars such as corn, cassava or sugarcane, PLA offers many of the functional properties of conventional plastic while being designed to break down in commercial composting environments. PLA, as is a natural polymer, is designed to substitute widely used petroleum-based plastics like PET (polyethylene terephthalate).

What is PLA?

One of the first bioplastics, PLA (polylactic acid) is a biopolymer produced through the fermentation of plant carbohydrates, such as corn starch, cassava or sugarcane. Fermentation creates lactic acid, and then, via polymerisation, lactic acid molecules are linked into chains, forming PLA resin — a durable plastic-like material.

The resin is then cooled and cleaved into pellets. Products are produced via extrusion, injection moulding, or thermoforming. Because PLA can be processed into films, coatings and rigid packaging formats, it has become a widely used material in compostable food packaging.

Unlike conventional plastics derived from petroleum, PLA is produced from renewable feedstocks. This means the carbon source used to produce the material is of plant origin rather than fossil fuels.

What is CPLA?

CPLA (crystallised PLA) is a heat-treated version of PLA that offers significantly higher temperature resistance. Crystallisation is achieved by applying high pressure and heat to PLA, making the material less susceptible to heat degradation to achieve heat resistance to 82ºC for coffee cup lid applications. 

READ MORE: Bioplastic misconceptions

CPLA coffee cup lid

Why PLA is used in food packaging

PLA is used across many compostable packaging formats because it offers several practical benefits for food service environments.

Food-contact safety

PLA is widely used in food packaging and complies with food-contact requirements in many markets, including regulations administered by the U.S. Food and Drug Administration (FDA). Migration studies conducted under FDA testing guidelines have shown that potential trace compounds released from PLA — such as lactic acid and related molecules occur at very low levels and ultimately convert to lactic acid, a naturally occurring substance found in many foods and in the human body.

Based on this evidence, PLA is recognised as safe for use in food-contact materials and is widely used globally in applications such as cups, lids, deli containers and food packaging films.

RESEARCH: PLA food-contact safety

Performance for cold food and drinks

Polylactic Acid (PLA) offers excellent performance for cold food and beverage packaging applications — clear containers, smoothie cups and lids, due to its high clarity and rigidity. PLA, however, is not suitable for hot food applications. Standard PLA begins to soften at temperatures above 45–55°C, causing deformation, lid seal failure, and leakage in hot, steamy, or microwaved scenarios. 

While clear PLA packaging is suited to cold applications, PLA is used as a thin barrier coating on paperboard. In these formats the paper fibre provides the structural strength and heat resistance, while the PLA layer acts as a liquid barrier. 

Versatility in packaging formats

Comparable to fossil-fuel plastic functionality and usefulness, PLA can be processed in various forms using many conventional plastic manufacturing techniques while retaining the functional properties of petrochemical plastics such as PET. PLA is most widely used in food and beverage packaging formats such as clear cups and lids, clear food containers, and lined paperboard items such as coffee cups and paper bowls  to achieve water and oil resistance.

Renewable feedstocks

PLA is produced from plant-derived sugars, typically sourced from crops such as corn or sugarcane. This means the raw material originates from renewable biological resources rather than fossil-based petrochemicals.

Industrial compostability

Certified compostable packaging is designed for circularity. 

Compostable plastics that are tested and certified according to the European standards for industrial composting EN 13432 (for packaging) or EN 14995 (for plastic materials in general) and equivalent ASTM D6400 and AS 4736 fulfil the technical criteria to be treated in industrial composting plants. These plants provide controlled conditions, i.e. controlled temperatures, humidity, aeration, etc., for a quick and safe composting process.

EN 13432 requires compostable plastics to disintegrate after 12 weeks and completely biodegrade after six months. That means that 90 per cent or more of the plastic material will have been converted to CO2. The remaining share is converted into water and biomass – i.e. valuable compost.

Duck Island customised PLA lined  FSC® MIX paper bowls

Is PLA compostable?

PLA can be composted when it is certified to recognised compostability standards and processed in appropriate facilities.

Certified compostable packaging is designed to support circular systems. Compostable plastics that are tested and certified to recognised standards such as EN 13432 (Europe), ASTM D6400 (United States) and AS 4736 (Australia) meet the technical criteria required for treatment in industrial composting facilities.

Industrial composting plants provide controlled conditions — including temperature, moisture and aeration — that allow materials to break down efficiently and safely.

Under the EN 13432 standard, compostable plastics must disintegrate within approximately 12 weeks and biodegrade within six months. During this process, the majority of the material is converted into carbon dioxide, water and biomass, which contribute to the final compost.

When composting facilities operate within these conditions, the likelihood of residual material is minimised. However, where facilities do not meet the required temperature or processing conditions, compostable materials may not fully break down.

In New Zealand, there are currently no national operating standards for composting facilities. While many packaging products are certified to global compostability standards, not all facilities reach the temperatures of 55–60°C or maintain the processing cycles required to achieve full biodegradation.

For this reason, some composting operators cannot accept certified compostable packaging, as the conditions needed to process materials such as PLA are not consistently available. Longer composting cycles — typically six to nine months may also present operational or economic challenges for some facilities.

This is why understanding local composting infrastructure is an important part of selecting compostable packaging.

READ MORE: Compostable materials in the real world: Scion x WasteMINZ

Ecoware supplies clear PLA products derived from corn-based plant sugars. These materials are certified for industrial composting to internationally recognised standards including ASTM D6400, AS 4736 and EN 13432.

Clear cold cups and lids

CPLA coffee cup lids

Clear food containers

Bin liners and coffee dump bags 

We also supply paper-based packaging that utilises PLA linings, which are similarly certified to global compostability standards. Examples include:

Paper PLA lined coffee cups

Paper PLA lined bowls and lids

Paper PLA lined noodle boxes

These packaging formats combine renewable materials with certified compostable systems designed to support food-waste recovery.

Exploring certified compostable PLA packaging for your business

If you’re material-curious or exploring ways to reduce reliance on petrochemical plastics, we’re always happy to talk. For product information, samples or custom branding enquiries, email hello@ecoware.co.nz to start the conversation.