Replacing plastic is currently very difficult
Packaging requirements for food, but above all for fish and seafood, are particularly demanding. Packaging needs to protect its perishable contents from spoiling and external influences while being as inexpensive as possible. Plastic packaging meets this requirements profile particularly well. But we wish to replace it with other materials because it is not sustainable. How realistic is this?
Plastic was once viewed as the ideal solution for many packaging problems. The material is light, offers endless design possibilities, is food-safe and is also relatively inexpensive. But the shocking extent of plastic waste in the seas has brought plastic into disrepute and made it the focus of public attention. Industrial and retail companies have recognised the problem and are looking for more environmentally friendly, sustainable packaging materials. But for fish in particular it is very difficult to replace traditional plastic packaging with materials with similarly good properties. Plastic packaging for fish and seafood products has been tried and tested over many years. It is safe, hygienic and taste and odour-neutral, which is particularly advantageous for moist fish products. A plastic covering also protects its contents from premature spoiling. It shields the product from negative external influences such as microorganisms, oxygen, light and mechanical stresses and often even expands and reshapes, which makes manufacturing temperature-insulating, salt and acid resistant containers and shipping boxes possible. Plastic containers, trays, wraps or bags are versatile and suitable for almost every application. Despite all of the justified criticism, plastic is simply optimally suitable for packaging purposes.
Packaging is usually designed for single use and as such it is an example of the convenience-based lifestyle in our modern throwaway society. As soon as its contents have been removed, it has fulfilled its purpose and becomes waste. Therefore anyone wanting to act sustainably must first change their lifestyle. Some problems would completely cease to exist if all consumers properly disposed of plastic packaging as soon as the products it contained were removed. And not just now and again, but every time, and also everywhere in the world. A pipe dream, as we know, since for one thing, many places lack functioning disposal options for recycling used plastic. And for another, many people are not at all as environmentally aware as they frequently claim themselves to be. Much packaging is carelessly thrown away after use, pollutes the natural world and then unfortunately often ends up in the sea. For this reason, the manufacturers and providers of products packaged in plastic are under pressure worldwide to find more environmentally friendly packaging materials.
The variety of packaging materials makes the search more difficult
Despite some ideas and progress in some areas, there is currently no prospect of a material that could replace plastic packaging completely in the near future. Sustainability is well-known not to be a short-term task, but rather an ongoing, continuous process that requires strategically oriented, wise action. Especially since the alternative materials must replace all traditional product coverings, i.e. wraps, boxes or insulating polystyrene cool boxes, for the storage, transport and retailing of fish products as well as for the takeaway business and online retail. And in addition to the actual packaging, this also includes other products such as strapping and adhesive bands or gel-filled cold packs and pads. Manufacturers, catering businesses and fish retailers must move away from tried and tested packaging practices and find new ways to continue to supply customers with products of the desired freshness and quality. The transition to recyclable, compostable or biodegradable packaging is a real challenge, especially since the costs for such materials are 30 to 50 percent higher on average. If these additional costs were passed on to the retail price in full, however, this could appreciably reduce the willingness of many consumers to buy the products.
Some plastic packaging can already be replaced by alternative materials, but their sustainability is also sometimes viewed critically by experts. If all MAP trays and folding cartons, wraps, delicatessen bowls, blister packs and polystyrene cartons made from plastic were completely replaced with containers made from glass, paper, tin cans or cardboard, this would more than double energy consumption. Glass, for example, is very suitable for recycling, but is highly energy-intensive to manufacture. Glass is also significantly heavier than plastic, which results in higher transport costs. It is also prone to breaking and is thus associated with certain risks when it comes to packaging food. Packaging manufacturers therefore face the challenge of developing completely new designs that meet hygiene, safety and labelling standards, guarantee the integrity and intactness of the packaged products, require less material if possible, and result in fewer greenhouse gas emissions associated with their manufacture. This requirements profile makes it clear that the development of more environmentally friendly and sustainable packaging requires new ideas and significant expertise.
The optimisation potential of plastic is being better exploited
Despite all of their problems and their poor image, thermoplastics will continue to play a very central role in the packaging sector for the foreseeable future. They simply offer too many advantages to be completely replaced yet. Nevertheless, there are some changes on the way in the use of plastic packaging which can be briefly expressed by the terms less, simpler and different. ‚Less‘ refers to the quantity of the plastic material used. Wherever possible, plastic is avoided (for example in viewing windows in cardboard packaging) and material saved, for example by rolling out plastic wrap more thinly or shaping thermoformed trays differently and designing them to be lighter. ‚Simpler‘ primarily means that the composition of the plastic packaging is significantly changed. Instead of standard wraps and trays that are often composed of several layers, which makes recycling them significantly more difficult or even impossible, monomaterials are increasingly preferred, which can re-enter the materials cycle after use much more easily. And ‚different‘ refers in particular to the type of plastic material used, that preserves the usefulness of the packaging, but also offers specific advantages, for example the incorporation of recycled plastics or of plastic based on natural raw materials.
Vacuum skin packaging, where the covering film wraps around the packaged product like a second skin, is a great example of these innovative packaging strategies that aim to be less, simpler and different. Recently it has increasingly also been used in retailing fish and seafood products. With skin packaging, film use is significantly reduced and mono APET films can also be used (APET stands for amorphous polyethylene terephthalate), more than two-thirds of which are composed of recyclate (chemically recycled plastic). The term ‚simpler‘ must therefore be qualified somewhat, since manufacturing these special films with defined shrink properties is of course an advanced technology. Skin packaging offers enormous advantages both for the manufacturer and for customers. The use of material and therefore the quantity of packaging waste saved is significantly reduced and customers can see the whole product. Integrated easy-peel corners also often make opening the packaging and removing the contents easier.
Reusability is the order of the day
Returning supposed plastic waste to the proper materials cycle is a model that is favoured by many in the packaging industry. Packaging made from recycled polyethylene terephthalate (rPET), a break-proof plastic that can be reused up to 25 times, also has a positive ecological balance due to its low transport weight. Recycled PET, which is used, among other things, for vacuum bags, MAP trays and other packaging, saves natural resources, protects the environment and contributes to reducing CO2 emissions. Traditional plastics therefore should not be prematurely written off. This also applies to expanded foamed polystyrene (EPS), from which heat-insulating polystyrene boxes are usually manufactured for the transport of fresh fish. These boxes are often already made from recycled polystyrene, without the performance characteristics of the packaging being in any way affected by this. Insulating boxes made from recycled EPS, usually called ‚Ccycled polystyrene‘ for short, are even suitable as primary packaging for fish. Ccycled boxes have “like-new” quality and are approved for direct contact with food.
Significant hopes are now resting on bioplastics, which are seen as particularly environmentally friendly, because they cause significantly less greenhouse gas emissions than standard plastic material. A study carried out in 2017 calculated that the switch from conventional plastic to bioplastic based on corn would reduce the USA’s greenhouse gas emissions by 25 percent. According to estimates, the global market for bioplastics is currently approaching 44 billion US dollars. Bioplastics for packaging in the food sector are usually made from polylactic acid (PLA) which is typically obtained from the sugars in corn starch, manioc or sugar cane. PLA looks like and has the same properties as polyethylene (PE) but is biodegradable, climate-neutral and often even edible. Other biodegradable plastics are made from polyhydroxyalkanoates (PHAs) that are created from organic raw materials by microorganisms that are often genetically modified. However, PHA plastics are only rarely used for single-use food packaging. Because they are particularly biocompatible, they are more often used in the medical sector, such as for suture material after operations, as artificial bone plates and for skin replacements. What makes the use of bioplastics in the area of packaging difficult at the moment is their higher prices. They are on average 20 to 50 percent more expensive than comparable conventional plastics. Prices do have a tendency to fall, because more efficient methods for producing bioplastics are being developed, but only slowly.
Bioplastics not as sustainable as is assumed
A study from the University of Pittsburgh from 2010 also cast doubt on the environmental friendliness of bioplastics. The cultivation of corn, manioc, sugar cane and other plants that serve as the basic raw materials for biodegradable plastics is claimed to lead to increased land use, require greater water and energy consumption than conventional plastics, increase the use of fertilisers and pesticides and also contribute to higher greenhouse gas emissions. The Plastic Pollution Coalition assumes that currently, an area of arable land greater than Belgium, the Netherlands and Denmark together would be required to meet the global demand for bioplastics. This is currently lacking for the cultivation of food. In addition, bioplastics – contrary to generally held assumptions – are not industrially compostable. Biodegradable plastics will 90% decompose at 60 degrees after a maximum of 12 weeks. Despite all of these restrictions and doubts, teams of researchers across the world are looking for new ways to make the production of bioplastics more efficient and cost-effective. At Michigan State University, experiments are being carried out with cyanobacteria (blue algae) which create chemical bonds using photosynthesis. The California startup Mango Materials is working on eventually being able to convert methane gas from sewage treatment plants or landfill sites into bioplastic. Researchers from the Centre for Sustainable Technologies at the University of Bath in Britain claim to have already found a cheaper way to make polycarbonate out of sugar and carbon dioxide.
Fish processors and retailers are not just ready in principle, but often actually have a keen interest in exploiting innovative packaging concepts. Doing without plastic would be somewhat easier, however, if the available alternatives were equivalent or at least had similar properties to previously used packaging. Finally, it is not just the avoidance of waste that needs to be taken into account, but also transport and logistics, product safety, hygiene and attractive product presentation.
Not every innovative packaging idea is actually mature and supermarket-ready. Some concepts that superficially appear to be quite acceptable have not yet been able to be implemented as hoped. These include packaging materials made from agar from red seaweeds, and edible and biodegradable wraps made from the milk protein casein or from the mycelium of fungi. Bioplastics made from wood biomass, energy grasses and crop residues, as well as lignin or cellulose, have barely passed the testing stage. Now and again disposable dishes and packaging made from bamboo can be found on the market, but critics doubt their sustainability, because many of these products are to a large extent composed of synthetic plastics.
Natural packaging materials are gaining ground
There are already environmentally friendly alternatives to polystyrene crates made from foamed plastic, namely reusable boxes and transport crates that are made of over 95 percent cardboard and can therefore simply be disposed of in the paper recyclables bin. Both fresh fillets and frozen products, for example, can be packed in folding cartons that can withstand even cold and damp conditions with a wafer-thin PE coating. Another interesting option is dimensionally stable and environmentally friendly packaging made from paper injection moulding. This is made solely from paper fibres, water and industrial starch and exposed to heat by baking and is therefore particularly environmentally friendly. Paper can be processed, coated and printed into very different products or folded into complex packagings with the help of complicated folding techniques similar to Japanese origami. The purpose of use is crucial for selecting the right material. Corrugated cardboard, for example, is light, dimensionally stable, has a long lifespan and also has very good insulating properties. Many of these features are also true of solid cardboard, but with the limitation that it has a lower insulating value, which makes solid cardboard boxes the ideal packaging for the energy-saving freezing and frozen storage of fish. Products in a solid cardboard box freeze about 35% faster.
Environmentally friendly packaging made from paper and cardboard is gaining in importance in the growing takeaway business as well. Snack boxes, moulded trays and boxes with folding lids have similarly good performance characteristics as previous packaging made from aluminium or plastic, and are therefore a sustainable alternative for burgers, baguettes, burritos or wraps. Even for challenging takeaway dishes, suitable paper boxes are now available. They usually have separate sections for the individual components, such as fish, sauce and sides, and can often even be reheated in the microwave if needed. After use, they can then simply be returned to the paper cycle via the paper recycling bin. However, even the use of paper in the area of packaging is now no longer completely uncontroversial, because the cellulose required often leads to the deforestation of entire forests, which are well-known to play an important role in climate protection. For this reason, packaging manufacturers are searching for suitable materials in this area as well, and they have hit on the composite cup plant (Silphium perfoliatum), among others. Sustainable papers and cardboards can be made from this plant species, which is native to North America, and is already being used for packaging perishable fish products such as hot smoked salmon. Cup plant paper is resource-efficient. Relatively little water and energy are required for the preparation process and the fibres are obtained without harmful chemicals. Its regional cultivation also shortens transport routes and reduces associated CO2 emissions.