Food packaging fulfils many different roles: it provides containment for the packaged food, a surface for branding, marketing and information alike, and allows for a convenient and speedy checkout at the cashier. Beyond that, it protects the food from contamination and the surroundings. By doing so, packaging can extend the shelf life of the packaged food. This article discusses shelf life and the role of packaging, challenges encountered when changing the packaging, and why it is important to consider shelf life in the context of sustainability surrounding food packaging.
What is shelf life and what role does packaging play in it?
Shelf life is the length of time for which a food or other commodity may be stored while being fit for use, consumption, or sale. After the shelf life has passed, the item in question is no longer suitable for use or sale. This is not always identical to the “best before”, “use by”, or “sell by” date found on food packaging which provides a minimum time guaranteed by the producer.
The shelf life of a food is usually determined through storage tests by the producer. In these tests, the food is packaged and stored in controlled conditions. Samples are tried by a trained panel in regular intervals to determine if the food is still in acceptable condition. The storage conditions can mirror those that are expected in real use, or they can be harsher to reach the shelf life faster or introduce safety margins. Shelf life simulations, using mathematical models to represent food and packaging, are another tool to predict the shelf life of food in different scenarios.
Modified atmosphere packaging (MAP): The package is filled with a gas mixture chosen to provide the right conditions for extending shelf life. Usually, the mixture is composed of certain amounts of oxygen, nitrogen, and carbon dioxide, different from our normal atmosphere. It is mainly used for meat but also nuts or salad. The modified atmosphere is lost over time, but packaging materials with high barriers and tight sealing can extend its effectiveness. |
Packaging can help in the extension of the packaged food, thus reducing waste. It does this by slowing down processes that lead to the spoilage of food – how exactly depends on the food and on how it spoils. Many foods are susceptible to oxygen, as it reacts with, for example, unsaturated fatty acids or vitamins. Water vapour can be absorbed by dry foods or lost by wet foods, changing the texture or mouth feel. Both oxygen and water vapour can migrate through packaging at different rates, depending on the material. For foods packaged under modified atmosphere, carbon dioxide can be another important gas which may be lost through the packaging over time. Carbon dioxide is applied to suppress microorganisms from growing; these are also affected by oxygen and humidity. The packaging should be designed to provide sufficient protection for the food to last for the shelf life, which can be achieved by choosing materials with the right barrier and sealing properties. A schematic representation of the processes in a MAP packaging is shown in Figure 1.
Another factor in spoilage can be light, which may bleach certain food ingredients (e.g. many spices) or accelerate oxidation. Here, not all wavelengths (colours) of light act in the same way. Making packaging completely opaque prevents damage by light but choosing a material with the right transmission properties can also be viable.

Besides gases, foods may (or be susceptible to) also lose liquids. A sufficient barrier against liquid water or grease and oil is required in those cases. Apart from the obvious example of beverages, foods like yoghurt, salads, or meat may produce liquid water, which should not leak out of the packaging. If this were to happen, it would not only lead to the package potentially feeling wet on the outside, but also to a loss of mass and a possible deterioration in the integrity of the packaging. Foods like butter or chocolate, for example, might lose some of the fats inside and lead to the package feeling greasy, if no fat barrier were provided.
For sensitive foods that require a high liquid barrier, it is also important that the formed package can be sealed tightly. Too many holes in the seams of a unit of packaging will allow air and humidity to be exchanged with the surroundings and can easily negate the barrier of the material itself and shorten the possible shelf life. Even if these holes can be quite small, which makes it hard to notice them, they may amount to considerable losses. This can be avoided by making sure that the material is properly sealable and that the sealing process is optimised (temperature, pressure, time).
This consideration on the role of packaging in the extension of the shelf life of foods show that the packaging must be chosen based on the needs of the food. Of course, the shelf life does not start at the store, but at the time of production and packaging. The logistics of the supply chain, from the production facility through transportation, storage in warehouses, and display in the store, to storage by the consumer must be considered.
What are the challenges for material substitution and reusable packaging related to shelf life?
Often, conventional food packaging consists of fossil-based plastics and is intended to be discarded after use. The packaging is usually optimised to the requirements of its content, the value chain, and for cost. Substituting the materials or changing to reusable packaging can impact shelf life, logistics, cost, and any other aspect of the life cycle. Here, we will focus on shelf life. The packaging for sensitive foods often is composed of different layers. Outer layers provide most of the structure and some protection to the inner layers. Layers that provide strong gas barriers are often thinner than and in between the main layers, protecting them from mechanical damage and other external factors that could compromise them.
Material substitution
Polarity and barrier properties: For a gas to pass through a material, it must first be dissolved in it (or be able to penetrate it) and then diffuse through it (or be able to move within it). Nonpolar molecules like oxygen dissolve well in nonpolar materials like polyolefins (PE, PP), but not in polar materials like EVOH or polyesters like polyethylene terephthalate (PET) and polylactic acid (PLA). The opposite is true for polar molecules like water vapour. These phenomena are like the immiscibility of water and oil. |
For shelf life considerations, packaging materials are chosen to provide the necessary protection. Fossil-based plastics can have good barriers against oxygen or water vapour, though usually not both, which is the reason for using multi-layer packaging materials. The very widespread materials polyethylene (PE) and polypropylene (PP), for example, display a good barrier against water vapour but are less protective against oxygen. They are often layered with the barrier material ethylene vinyl alcohol (EVOH) which provides an excellent oxygen barrier but is itself sensitive to humidity. The challenge when replacing fossil-based materials with paper-based packaging and/or bio-based polymers is to find the right substitutes displaying the right barrier and sealing properties, while offering a recyclable solution with a low environmental impact. [1] [2] [3] [4].

Paper as a packaging material for sensitive foods has one main issue: it lacks any meaningful barrier against oxygen, water vapour, or any other gases due to its porous nature. It can, however, provide a decent light barrier, especially brown paper. Thicker paper, carboard, or moulded fibres (e.g. egg cartons) can also provide some mechanical protection for fragile food.
To turn paper into packaging material for sensitive foods, it is often coated with one or several barrier layer(s). [5] Here, it is important to choose to find the most suitable materials and the best multi-layer combination, to avoid disturbing as much as possible the recycling/repulping process. Making the barrier layer as thin as possible is a proven strategy. Fossil-based polymers are the most used (laminate film, coating etc.), since they provide very good sealing and barrier properties. Since nothing beats a layer of metal when it comes to barriers, even polymers with an aluminium layer (foil or vacuum deposition) can be used to boost gas barriers. Beverage cartons are a widespread example of this, though they also are a special case as they have their own recycling stream.
Bio-based polymers or plastics are an alternative to conventional fossil-based plastics (PE, PP, PET) to allow the use of renewable sources coming from biomass, e.g. bio-PE, bio-PP, and may even be biodegradable in certain environments for some of them (ex: starch, proteins, PLA, polyhydroxyalkanoates PHAs). Some biopolymers are also fibre-based, e.g. micro fibrillated cellulose (MFC), and can therefore be counted as part of the paper ratio of the final packaging solution and ease the recycling. Some bioplastics as PLA, PHA or PEF can directly be used as a replacement for conventional plastics, even if their barrier, mechanical and sealing properties need to be adapted and optimised. [6] However, fossil-based plastics still vastly overshadow biobased plastics in production. As is shown in Figure 2 for the year 2022, they are the largest contribution to both global and European plastics production, followed by mechanical recycling-based plastics. [7] Bio-based plastics only make a small contribution to total production (for example, on a European level in 2022, 47.2 Mt of plastics were produced from fossil sources, only 0.7 Mt from bio-based sources).
Different challenges and issues must be considered with bio-based polymers/plastics:
While a good oxygen barrier is achievable for many materials, water vapour barrier is usually more critical for several reasons: most of them display a polar character on a molecular level and/or are water sensitive. They can be functionalised with hydrophobic groups, or mixed with additives or loads to increase the water vapour barrier;
The raw materials used are sometimes derived from food resources and ethically conflict with food crops, though agricultural waste-streams offer interesting alternative sources [8];
Most of these bioplastics or biopolymers are still in the development phase or are not available in sufficient quantities to produce large volumes of packaging (often necessary in the food industry);
Their processability is not yet fully understood and optimised on existing packaging line equipment, sometimes requiring a significant number of iterations.
Reusable packaging
In contrast to the widespread disposable packaging, reusable packaging is not intended to be discarded after use. Instead, it can be cleaned and used again – ideally several times. This poses some challenges on the packaging to protect its contents repeatedly. The packaging must be sturdy enough to withstand repeated use and the cleaning process. Cleaning the packaging is important to prevent contamination of the new filling with – possibly spoiled – residues of the last. Not only must the packaging be made of a material with a sufficient barrier, but just as disposable packaging must be able to be sealed, reusable packaging needs to be closed tight to avoid losing the barrier to unintended gaps. This is provided the packaged food requires such a barrier – if the packaging acts mostly as a container, it still needs to be closed tight enough to avoid accidental spillage or contamination with dirt. The closing is mostly related to the structural design of the packaging and must also be build such that the material is not damaged in a way that compromises its protective function by the opening and closing of the package.
Since reusable packaging goes through several use cycles, the material must be sturdy enough to withstand repeated use and cleaning. This may require protecting the functional layers of the packaging from damage, e.g. by sandwiching these between thicker layers of the material providing the structural stability than would be required for disposable packaging. [9]
Why are shelf life considerations important?
Producing packaging requires energy and resources, and typically produces waste. On the other hand, packaging extends the shelf life of the packaged food. For most foods, the resources that go into the production of the food far outweigh what is required to make the packaging. The cost in resources and energy for production, transport, and disposal is summed up in the environmental footprint. If the packaging, by preventing food waste, saves more resources than it costs, it lowers the environmental footprint of the packaged product. This makes a direct comparison of two packaging materials difficult if they differ in their protective function. [10] In a study by Verghese et al., the contribution of consumed food, wasted food, and food packaging over the weekly consumption of different families was compared. As shown in Figure 3, the comparison showed that the food production has the largest contribution to greenhouse gas emissions for different types of food, followed by food waste. The contribution from the packaging generally comes in third, even for minimally processed foods like fruits, vegetables, and nuts. The notable exception are beverages, which includes bottled water and glass bottles. [11]

Many factors go into the environmental footprint. The extraction of resources (e.g. fossil vs renewable) and end-of-life (recycling, composting, incineration, landfill) are prominent and may immediately come to mind. Additional steps like production and transport are sometimes less prevalent in discussion but are also important to consider and can have a sizeable impact. Lightweight materials generally perform well in transportation, as the energy cost for shipping generally goes up with the weight of the transported good – the less the packaging contributes to the weight of the total product the better, especially at longer distances. This affects both disposable and reusable packaging: disposable packaging has to be transported from the production plant to the store, while reusable packaging also has to be transported from collection points to cleaning facilities. [10] [12]
How does the interplay of shelf life and packaging factor into the environmental footprint? If the packaging underperforms, more food will be wasted, which incurs a steep environmental impact. On the other hand, overpackaging will lead to a needless use of resources and energy in the packaging. Thus, there is a sweet spot, where just enough packaging is used to minimise the environmental footprint. To find this sweet spot, it is not necessary to extend the shelf life as long as possible. Rather, the shelf life should be sufficient that enough of the food is consumed before it spoils. Thus, some average of consumption behaviour must be considered as well. [13]
Figure 3 The contributions to greenhouse gas emissions from consumed food, wasted food and packaging in different food categories for one family over a week. [11] |
The sweet spot between under- and over-packaging depends on the shelf life of the packaged food and the logistics. The logistics in turn play into the shelf life of a given combination of food and packaging. Disentangling these interconnected relations in full requires a good understanding of how the food spoils, how much protection the packaging affords, how long the packaged food spends in transport, storage and store, and how long the consumer stores the package before consumption. But given how much the food contributes to the environmental footprint of the full package, its shelf life is too impactful to ignore when assessing alternative approaches to food packaging.
References
[1] | A. T. Nguyen, L. Parker, L. Brennan und S. Lockrey, „A consumer definition of eco-friendly packaging,“ Journal of Cleaner Production, Bd. 252, p. 119792, 2020. |
[2] | A.-S. Bauer, M. Tacker, I. Uysal-Unalan, R. M. S. Cruz, T. Varzakas und V. Krauter, „Recyclability and Redesign Challenges in Multilayer Flexible Food Packaging - A Review,“ Foods, Bd. 10, p. 2702, 2021. |
[3] | P. Tyagi, K. S. Salem, M. A. Hubbe und L. Pal, „Advances in barrier coatings and film technologies for achieving sustainable packaging of food products - A review,“ Trends in Food Science & Technology, Bd. 115, pp. 461-485, 2021. |
[4] | A. Mengozzi, D. Carullo, F. Bot, S. Farris und E. Chiavaro, „Functional properties of food packaging solutions alternative to conventional multilayer systems,“ Journal of Food Science and Technology, pp. https://doi.org/10.1007/s13197-024-06038-5, 2024. |
[5] | M. Mujtaba, J. Lipponen, M. Ojanen, S. Puttonen und H. Vaittinen, „Trends and challenges in the development of bio-based barrier coating materials for paper/cardboard food packaging; a review,“ Science of the Total Environment, Bd. 851, p. 158328, 2022. |
[6] | F. Versino, F. Ortega, Y. Monroy, S. Rivero, O. V. López und M. A. García, „Sustainable and Bio-Based Food Packaging: A Review on Past and Current Design Innovations,“ Foods, Bd. 12, p. 1057, 2023. |
[7] | P. Europe, „Plastics - the fast Facts 2023,“ [Online]. Available: https://plasticseurope.org/knowledge-hub/plastics-the-fast-facts-2023/. [Zugriff am 08 11 2024]. |
[8] | S. Ranganathan, S. Dutta, J. A. Moses und C. Anandharamakrishnan, „Utilitization of food waste streams for the production of biopolymers,“ Heliyon, Bd. 6, p. e04891, 2020. |
[9] | V. Lofthouse, R. Trimingham und T. Bhamra, „Reinventing refills: guidelines for design,“ Packaging Technology and Science, Bd. 30, pp. 809-818, 2017. |
[10] | E. Svanes, M. Vold, H. Moeller, M. K. Pettersen, H. Larsen und O. J. Hanssen, „Sustainable Packaging Design: a Holistic Methodology for Packaging Design,“ Packaging Technology and Science, Bd. 23, pp. 161-175, 2010. |
[11] | K. Verghese, E. Crossin, S. Clune, S. Lockrey, H. Williams, M. Rio und F. Wikstrom, „The greenhouse gas profile of a ‘Hungry Planet’; Quantifying the impacts of the weekly food purchases including associated packaging and food waste for three families.,“ in 19th IAPRI World Conference, Victoria University, Melbourne, Australia, 2014. |
[12] | P. Yadav, F. Silvenius, J.-M. Katajajuuri und I. Leinonen, „Life cycle assessment of reusable plastic food packaging,“ Journal of Cleaner Production, Bd. 448, p. 141529, 2024. |
[13] | H. Williams, A. Lindström, J. Trischler, F. Wikström und Z. Rowe, „Avoiding food becoming waste in households - The role of packaging in consumers' practices across different food categories,“ Journal of Cleaner Production, Bd. 265, p. 121775, 2020. |
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