In search of the most sustainable form of food packaging

Food packaging remains one of the key bottlenecks in the development of a sustainable food system.

Ascertaining which food packaging material is the most sustainable is difficult, given the many ways you could judge such a thing.

“The most sustainable solution for any given food application depends on the specific attributes and requirements of the product,” explains Tim Sykes, brand director at Packaging Europe.

“What are its barrier requirements? What shelf life does it need? In what other ways should it be protected?

“In addition, the waste footprint and the carbon footprint of the packaging will vary, depending on local collection and recycling infrastructure and factors such as distance travelled and energy sources used for electricity generation in the region. It’s complicated.”

Plastic

Plastic is not usually considered the most sustainable form of packaging among consumers. And indeed, in many ways, it’s not.

“The plastic waste crisis highlights many of plastic packaging’s cons; it relies on fossil fuels, which are limited and carbon-intensive resources. While it is recyclable in theory, packaging can consist of several layers made of different plastics, which complicates the process,” says Sykes.

Unrecyclable plastics can lead to environmental pollution and take centuries to break down, he explains. And when they do, they can contaminate earth and waterways with microplastics and substances like PFAS.

Nevertheless, there is nuance. Plastic, as an overall category, is more sustainable than others when sustainability is judged by carbon efficiency, Sykes explains.

Furthermore, not all plastics are as bad as others. According to Sykes, polyethylene terephthalate (PET) is one of the strongest contenders for most sustainable form of not just plastic, but food packaging in general.

PET, according to Sykes, is safe for direct contact with food and does not require treatments that could impact its recyclability or lead to health hazards (PFAS, for example).

It’s lightweight, which helps to save energy and emissions in transit, and it is both strong and durable, keeping food safe for longer and preventing food waste in both rigid and flexible applications.

The wide use of its recycled form (rPET) means that the development of virgin PET can be cut down.

Nevertheless, he stresses, it’s still a fossil-based substance, and has environmental implications if handled irresponsibly.

Glass

Glass is easy to make, as it is made from abundant materials such as sand, limestone, and soda ash. It is also considered a permanent material as it can be recycled many times without impairing quality.

Nevertheless, the process by which it is made is energy intensive, as it calls for high temperatures.

Despite its usefulness, glass’s rigidity and breakability means that there are limits to how it can be used and recycled.

“In theory, glass can be reused multiple times – but its cons include its breakability,” explains Sykes.

“Broken glass shards are not yet accepted at many recycling plants due to their size or safety risks to handlers in manual sorting processes. Its recyclability depends on the waste glass, or cullet, being free of contaminants and sorted by colour, which can pose challenges in the recycling process.”

Paper

In terms of renewability and recyclability, paper would win out, accord to Packaging Europe’s Sykes.

In renewability, especially, paper is clear winner. “Obviously, paper is derived from trees, which can be replanted; therefore, it is a renewable resource. If this is not handled sustainably, though, paper packaging production can contribute to deforestation.”

In terms of the production process as well, paper does well: while pulping, refining and mixing do require significant amounts of water and energy, its production is not as carbon intensive as glass or aluminium.

Paper is widely recycled and recyclable. Nevertheless, the application must be taken into account. Despite its recyclability in other contexts, paper becomes waste after contact with greasy food.

Furthermore, when recycled, quality degrades over time, and its life is shorter due to its lower durability. Nevertheless, it is often said to be compostable and biodegradable at end of life.

Some papers may require coatings to make them more durable and to ensure their functionality, sacrificing their recyclability.

Paper-based cartons, such as Tetra Pak’s, can have a lower environmental impact than other forms of packaging, according to Berit Hoffmann, northern Europe marketing, channel and retail director at Tetra Pak.

She points to a series of life cycle assessments (LCAs) finding that beverage cartons showcased ‘lower climate impacts’ than other forms of packaging.

“The relatively high share of plant-based material used in cartons was identified as the key reason for their lower carbon footprint compared to fossil-based plastics packaging,” she suggests.

Aluminium

Aluminium packaging is like glass considered ‘infinitely’ recyclable, according to Sykes, and this recycling process only uses around 5% of the energy needed to create new aluminium.

A lightweight, durable material compared to glass, it is recycled around the world.

Nevertheless, also like glass, creating it is highly energy intensive.

“It requires the extraction of the raw material bauxite, which has significant environmental drawbacks; and the smelting process emits sulphur dioxide and nitrogen dioxide, both of which contribute to smog and acid rain.”

Biobased

Beyond these more traditional form of packaging, some companies are developing ‘biobased’ packaging, often using side-streams from other industries.

While these are mostly at pilot scale at the moment, Sykes explains, and are therefore still quite expensive, they are becoming increasingly available.

One of these is seaweed, which can be utilised for dissolvable pods, flexible films, takeaway packaging and even cutlery, or make enhancements to existing packaging.

Sykes stresses that the industry developing seaweed packaging takes care not to harm marine life.

Seaweed has substantial sustainability benefits in its growth.

“Whereas paper requires trees to be grown, felled, and replanted, seaweed does not need arable land or fertilizers to grow. It thrives in both the ocean and freshwater, and comes with the added bonus of absorbing carbon.”

Another biobased material is lignin, a natural polymer which is derived from plant cell walls and often found in trees. It is currently being used to replace bisphenol A in epoxy resins.

Peatland plants are also being turned into paper packaging, replacing conventional wood.

Finally, polymers such as PET and PE are being derived from organic, rather than fossil, feedstocks.

Investment in this is growing, explains Sykes, and he hopes that more everyday plastics will be created like this in the future.