Hidden plastics: summary
- Hidden plastics are common in packaging, especially in drinks, as they’re used as inner layers in cans, cartons and pouches that appear plastic‑free
- These layers are essential for durability and shelf life, but are hard to recycle
- Most consumers are unaware, creating a disconnect between perceived and actual plastic use
- Health concerns and regulation are rising, pushing manufacturers to find alternatives
- Solutions are emerging but limited and face regulatory hurdles
For all the pushback against plastics, the material remains widely embedded in food and drinks packaging.
From vacuum-packed fruit and veg to yoghurt pots, black plastic meat trays and milk jugs, the material is seemingly everywhere shoppers look.
Crucially though, it’s also in many places they might not expect, quietly layered onto packaging that ostensibly appears to be plastic-free.
And few places is this more evident than in the drink’s aisle.
Be it aluminium cans, paper-based cartons or pouches, the category is awash with these so-called hidden plastics, typically used as a functional layer to ensure more resilient containers or longer-lasting contents, but arguably just as problematic as more visible plastics when it comes to both health and the environment.
These thin layers can make up a significant proportion of the packaging’s overall composition after all. For example, the average shelf-stable or refrigerated carton contains 20-22% polyethylene, according to the Carton Council of Canada (CCC).
So, given that 91% of global consumers are concerned at the proliferation of plastic waste, according to the UN, isn’t now the right moment to revaluate these small but impactful uses of plastic? How challenging might that be? And there any viable alternatives on the horizon that industry could be looking to scale up?
Disguising plastics in plain sight
For Sian Sutherland, co-founder and chief changemaker at A Plastic Planet, the drinks sector is one of the biggest offenders when it comes to the infiltration of hidden plastics.
“Most consumers have no idea that the inside of a drinks can is typically lined with plastic or that cartons marketed as sustainable often contain layers of plastic polymers fused with paper and aluminium,” she says. “The industry has become extraordinarily skilled at disguising plastic in plain sight.”
That matters, she says, because it misleads conscious consumers into believing they’re reducing how much plastic they load up into their shopping basket, when the reality is quite different. “People believe they are moving away from plastic when, in reality, they are still consuming it, touching it and ultimately discarding it into the environment only for it to end up back in our bodies.”
In some applications, these thin plastic layers can even compound the environmental waste. Composite packaging often combines plastic alongside paper and aluminium in tightly bonded layers using adhesive that are then difficult to separate using standard recycling processes.
Health concerns
In other applications, it is less the environmental impact and more concerns around health that have seen campaigners push for an alternative.
For example, the plastic coating used in aluminium drinks cans is negligible in volume, explains Krassimira Kazashka, CEO at to Metal Packaging Europe. “Thinner than human hair, the [plastic] coating is applied to a metal substrate to deliver specific technical performance,” she says. Technically, it isn’t even classed as a plastic by EU regulations. And significantly, the “ultra-thin, high-performance coatings used on metal packaging are completely removed during the melting process in recycling furnaces”.
But that hasn’t stopped questions being asked about its impact on human health.
“We now know plastic is not just a waste issue, it is a human health issue,” says Sutherland. “Microplastics and associated chemicals are being found throughout the human body, from blood and lungs to placentas.”
Already, regulators have clamped down on the industrial chemicals commonly used to manufacture these plastic coatings, amid fears they could leach into the contents.
Bisphenols, most typically Bisphenol A, have been used to manufacture epoxy resin linings for years, but have been shown to disrupt the endocrine system when ingested, explains Robert Fleming, entrepreneur in residence at Deep Science Ventures, the part of the body that regulates metabolism, reproduction and development.
“BPA and other related bisphenols, often referred to as ‘regrettable substitutions’ can lead to infertility, obesity, cardiovascular disease and cancer,” he says, with one study by environmental consultancy Systemiq estimating a global annual health burden as high as $227bn.
In one 2023 report by the European Environment Agency, drawing on the findings of an EU human biomonitoring research project, it was estimated that between 71% and 100% of people taking part across 11 EU countries were exposed to “above safe health thresholds” of BPA as a result of food containers, but also reusable water bottles and drinking water pipes.
As a result, the European Food Safety Authority (EFSA) first reduced the allowable threshold for BPA by a factor of 20,000 in 2024 and has since banned it completely, with companies given until January 2028 to eliminate BPA and its derivatives from can linings.
What is the solution?
As both consumers and regulators push for alternatives to these hidden plastics, the drinks sector faces an uphill battle in identifying workable, cost-effective solutions that deliver the same functional benefits as plastic.
In paper-based cartons, these plastic layers act as a crucial protective barrier between the packaging and its contents to maintain structure and a waterproof seal.
In aluminium cans meanwhile, “this protective layer is essential to the outstanding properties of metal packaging, helping to preserve product integrity, prevent corrosion and deliver a shelf life of up to five years”, says Kazashka.
Finding a workable alternative can take up to a decade, she adds.
“Transitioning to a new coating is complex and requires extensive testing and approval to meet strict safety and performance requirements, including safety compliance. It must be fully approved for food contact, should be resistant to food contents and high-temperature sterilisation, have no impact on taste or smell, show strong adhesion to metal and flexibility during manufacturing, and provide an effective barrier and consistent application across different factory conditions.”
Fleming is yet to see innovation on the market that ticks all these boxes.
"“Plastic became dominant because it is cheap, versatile and heavily subsidised by fossil fuel economics, but not because it is the only possible solution."
Sian Sutherland, co-founder and chief changemaker at A Plastic Planet
“Companies have found it difficult to find drop-in replacements for bisphenols without compromising on cost and performance,” he says. “I personally don’t believe enough research funding has been dedicated to solving this problem.”
The closest manufacturers have come, in his view, is V70, a can lining epoxy material created by Valspar, which uses the alternative Tetramethylbisphenol F (TMBPF). “However, we have further to go, as TMBPF appears to be less toxic than BPA and related but a new study published in Nature in 2024 suggests TMBPF may be obesogenic [contribute to weight gain] and a metabolism disruptor.”
With enough investment and focus from industry, Sutherland believes alternatives can be developed. “Plastic became dominant because it is cheap, versatile and heavily subsidised by fossil fuel economics, but not because it is the only possible solution.
“Of course, functionality, product preservation and shelf-life stability matter,” he says. “But we have to stop pretending the current system is the endpoint of innovation. Industry often frames this as an impossible trade-off between performance and sustainability, when in reality it is a question of investment, regulation and urgency.”
Rethinking drinks packaging from scratch
There is innovation emerging that is already moving the dial.
In December last year, for example, Tetra Pak unveiled what it says was the first-ever use of its paper-based barrier technology for juice cartons, an innovation that didn’t ditch plastic coatings completely but did switch to plant-based rather than fossil-based polymers and, in so doing, pushed renewable content to 92% and reduced carbon footprint by 43%.
In Japan and parts of Scandinavia, there is also growing investment in advanced fibre-based packaging designed to reduce plastic layers in cartons and beverage containers, says Sutherland. “We are also seeing innovation around bio-based coatings and alternative barrier technologies aimed at replacing fossil-derived plastic liners.”
At Deep Science Ventures too, Fleming says the team is supporting the research and development of a bio-based resin designed for can linings and paper coatings. “The intended resin is non-toxic, bisphenol free, scalable, cost effective and will be food-contact approved, and meet the performance requirements for the food and beverage industries.”
But many specialist start-ups in this space aren’t looking to replace the role of plastic liners in existing drinks formats, they’re rethinking the format from scratch.
London-based Notpla, for example, has spent the last decade developing its seaweed-coated containers and edible liquid bubbles. The latter, Ooho, is an edible, tasteless and biodegradable membrane made from seaweed that can be used to contain water and other liquids in a small ‘bubble’ and is suitable for drinks, sauces and other single-use liquids.
Pulpex meanwhile, which has won early support from fmcg heavyweights such as Diageo and Unilever, has created what it says is a patented fibre-based, single-mould paper bottle made from responsibly sourced wood pulp. The company is currently constructing its first commercial-scale bottle manufacturing facility in Glasgow, Scotland, which it says will be capable of producing 50 million of the cellulose-based bottles annually.
And in 2024, Danish start-up Paboco and Swedish manufacturer Blue Ocean Closures collaborated to create what they say is the industry’s first market-ready paper bottle and fibre-based cap combination.
Outlining the scale of the challenge though, 15% of this paper-based bottle’s material composition is still an HDPE barrier. The company has described it as a “minimal barrier solution” but one that doesn’t leave shoppers with a plastic-free option.
Building better systems
Putting an end to drinks’ hidden plastic problems will take time, admits Sutherland.
“Change of this scale does not happen overnight,” she points out. “It starts somewhere. Once innovation, investment and regulation begin shifting away from fossil-derived plastics, that momentum spreads across industries.
“What feels unavoidable today can quickly become outdated once better systems and materials begin to emerge. Similarly with reuse, once infrastructure and incentives are in place, behaviours can shift remarkably quickly.”
And it all starts with ditching the disguise.