Packaging seals: a key factor for long shelf life and product preservation

How packaging is sealed is an important issue, as it has a direct impact on the quality of the product and the packaging itself. A good seal preserves the product and maintains its organoleptic properties, as well as ensuring it is tamper-proof and extending its shelf life. It also guarantees a positive experience for the user.

HOW OFTEN HAVE YOU STRUGGLED TO PEEL BACK THE FILM ON A TRAY, OR FOUND IT TEARS AND BREAKS ON OPENING?

The seal on packaging has to be suitable for both the product itself and the material used.

Problems with user experience can be solved by correctly sealing the packaging, in other words, ensuring the optimal temperatures and pressures are used for each type of film during the packaging process, taking into account the thickness of each material.

One factor that can result in packaging being sealed incorrectly is the speed of production. This is often the result of a failure to make the necessary adjustments when changing materials, in an attempt to save time.

TYPES OF SEALING

COLD SEALING

Many food products, such as chocolate and ice cream, can be damaged by the heat of hot-fill sealing systems. For these products a cold seal system is used. This system doesn’t use heat, just pressure and special self-sealing adhesives. 

With the cold seal system, there is less adhesive force and the seal is less hermetic, meaning the packaging can be opened easily.

HEAT SEALING

Heat sealing, or thermal-bonding, is the most common form of sealing in the packaging industry because of the excellent results it provides. It consists of using heat to weld one thermoplastic to another thermoplastic, or another material, at a certain temperature and pressure. Hot plates or hot bars are normally used to apply heat to very specific areas of the packaging. In the production of pouches or other flexible formats, this type of sealing is used to weld the perimeter, or seal the ends.

The most common types of heat sealing are:

  • Hot-bar welding
  • Continuous heat sealing
  • Impulse welding
  • Hot-wire welding
  • Induction sealing

VACUUM PACKING

Vacuum packing consists of removing all the air from inside the packaging before sealing, thereby extending the expiry date of the product. There are many advantages of vacuum packing, although they can be summarised as hygiene and quality.

Vacuum packing preserves the taste and aroma of food. With this type of packaging, external smells are prevented from entering, and the aromas are of the food are prevented from leaving, meaning the food maintains its initial properties. As there is no oxidation or dehydration, the taste also remains the same.

SEAL QUALITY IMPACTS REPEAT PURCHASES 

As we have seen, a proper seal is essential for a good consumer experience. Of course, ensuring a product’s packaging correctly preserves its qualities is one of the primary aims. However, ease-of-use is also a main concern for consumers, and their repeat purchase of the product will depend on it.

An easy-peel seal is essential if you want to prevent user frustration. If a product requires too much time or effort to open, consumers will reject it.

This issue is of particular concern for the elderly, as studies have shown packaging that is difficult to open can directly affect their nutrition.

SEALING HELPS PREVENT FOOD WASTE

It is also important to remember that the quality of the seal directly impacts the shelf life of a packaged product and, therefore, it directly affects food waste. In Spain alone, 7.7 million tonnes of food is wasted each year. Good-quality seals would reduce these figures considerably.

In order to extend the shelf life of a food product, we have to stop the effects of agents that can cause its deterioration, such as light, moisture, temperature and oxygen. Coupled with a good seal, the use of barrier materials is essential for this purpose.

Check out our webpage for more information on the work of SP Group, and please do not hesitate to contact us if you have any queries. Our team of professionals will be more than happy to help.

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