We often visit supermarkets and hypermarkets and look for milk and other beverages in tetra pak and pouch packaging. We found out that Tetra Pak offers a longer shelf life than HDPE or other pouch packaging, even if the composition of the content in both packaging materials is the same. The secret behind the longer self-life is due to the multiple layers of the tetra pack, which protect air, light, and bacteria. Let’s look closer at the different layers of a tetra pack.
Let’s have a closer look at its layers
Tetra Packs are composite materials that contain layers of paper, plastic, and aluminum. Composite materials are made by bonding two or more materials from the same or different groups of materials to strengthen their weaknesses and bring out superior characteristics together. These tetra packs are made up of approximately 75% paper, 20% low-density polyethylene, and 5% aluminum.
The layers of tetra packs from outside inwards are as follows:
- Polyethylene
- Cardboard
- Polyethylene
- Aluminum foil
- Polyethylene
- Polyethylene
Fig. Layers in tetra packs
The objective of using different materials together is to increase flexibility and durability and to combine the unique characteristics of each material collectively. Each of the layers is systematically placed to ensure that it provides the required function as follows:
- The first polyethylene layer provides protection against external factors and moisture. It acts as a waterproof layer as well.
- The next cardboard layer provides strength to the overall pack and provides stability so that it can stand. This is the main layer, made from wood, which is the thickest layer among all layers. It increases the durability of the overall pack.
- Again, this cardboard layer is coated with a polyethylene layer which acts as an adhesive layer. The aluminum layer, which is placed in the next layer, cannot stick to the cardboard, hence a polyethylene layer is placed between the aluminum foil and the cardboard to provide the required adhesion.
- The next layer is of aluminum foil. The purpose of this layer is to provide protection against oxygen, flavor, light, and moisture, and act as a UV radiation barrier.
- Further, the foil is coated with a polyethylene layer, which again acts as an adhesive layer.
- Further, this polyethylene layer is coated with one more polyethylene layer, which acts as a liquid sealing layer. This layer is in direct contact with the product.
All layers together make tetra packs such as convenient and easy options while providing the benefits of improved shelf life, no need for refrigeration, preserving the nutritional value of the product, and keeping it safe. One more component that contributes to these benefits is Ultra High Heat (UHT) treatment.
What is UHT treatment?
UHT treatment includes heating each particle of a food product to the temperature of 134-135°C for a few seconds to ensure that the food product is free from harmful microorganisms and ensure safety for consumption. UHT treatment not only keeps the product free from harmful microorganisms but also helps to preserve the flavor and nutritional value of the food product. This treatment allows tetra packs to store perishable food products like milk, juices etc, without refrigeration, making them a highly practical solution for consumers, particularly regions having limited refrigeration facilities.
Tetra packs have revolutionized the global food and beverage market enabling products to be transferred across long distances, reducing significant amounts of food waste. While these packs offer convenient solutions, they come with great challenges and environmental concerns as well. Let’s have a closer look at the environmental concerns that they come along with;
Challenges in Tetra Packs
High resource consumption: The production processes of such materials require a large amount of water and energy. At the same time, the extraction or production of raw materials such as aluminum foil and paperboard has environmental impacts.
Difficulty in recycling: as these materials consist of various layers, it makes it difficult to separate each layer during recycling, which results in a lower recycling rate than that of normal packaging.
Deforestation and landfill waste: sourcing paper pulps to make cardboard contributes to deforestation if sustainability practices are not followed properly. At the same time, if these tetra packs are not recycled properly, they can end up in landfills, which contributes to waste accumulation, raising environmental concerns.
Non-biodegradability: these materials are not biodegradable or do not break down naturally, accumulating in the environment for a longer period.
So next time while picking a tetra pak, keep in mind both its benefits as well as the environmental concerns it brings along. While Tetra Pak is a clever packaging solution, it is also important to be mindful of its environmental concerns and explore ways to recycle and manage waste more effectively, while exploring more eco-friendly and sustainable packaging materials choices.
References:
Huijuan Dong, Feng Yu, Zhujie Bi, Chenyi Zhang, Xiao Liu, Yong Geng, Satoshi Ohnishi, Haifeng Li, Life cycle environmental and economic assessment of Tetra Pak recycling technologies, Resources, Conservation and Recycling, Volume 202, 2024,107355, ISSN 0921-3449.
