The 8 barriers of food packaging: a practical guide.
Where a barrier is needed, the right material makes the difference between a product that lasts and one that spoils. Here are the eight barriers that matter most.
· Fabrizio Luti
Why talk about barriers
Food packaging protects the product from what is outside and keeps in what is inside. Every product has its own enemies: for coffee they are oxygen and light, for a biscuit moisture, for a cheese in modified atmosphere the loss of gas.
How barrier is measured
Two values recur in technical data sheets: OTR, the oxygen transmission rate (cm³ per m² per day), and WVTR, the water vapour transmission rate (g per m² per day). The lower the value, the higher the barrier. Values can only be compared at the same test temperature and humidity.
| Barrier against | What it causes | Typical products | Typical materials |
|---|---|---|---|
| Oxygen | Oxidation, loss of colour and aroma | Coffee, grated cheese, nuts, snacks | Aluminium, metallised films, EVOH, AlOx/SiOx coatings |
| Oxygen and light on fats | Rancidity | Fried snacks, nuts, butter, grated cheese | Aluminium, metallised films, opaque or pigmented films |
| Water vapour | Loss of crispness, caking | Biscuits, crackers, powders, chewing gum | PE, PP, aluminium, paraffin-coated and waxed papers |
| Water and condensation | Paper that weakens, labels that peel off | Ice cream, frozen food, butter, bottles in the fridge | PE-coated papers, PE laminates, adhesives for the cold |
| Light and UV | Fat oxidation, discolouration | Dairy products, sliced cheese, oils | Aluminium, white or pigmented films, aluminium-laminated paper |
| Gas (modified atmosphere) | Loss of the gas mix | Fresh cheese, cured meats, fresh pasta | Structures with EVOH, PA, barrier PET |
| Aromas and odours | Loss of aroma or uptake of external odours | Coffee, tea, spices, confectionery | Aluminium, PET, barrier papers |
| Grease and oils | Stains, migration | Butter, chocolate, bakery products, pet food | PE-coated papers, PFAS-free grease-resistant papers |
Typical examples from technical literature: the solution for a given product is always verified with trials and technical data sheets.
Barrier and recyclability
With the EU PPWR regulation, recyclability becomes a requirement. Many traditional barriers, such as aluminium, can be replaced by mono-material structures and thin barriers; in other cases product protection remains the priority. It is decided case by case.
Frequently asked questions
Which barrier is the most important?
The one that protects against the product’s main enemy: oxygen for coffee, moisture for biscuits, gas for fresh products in modified atmosphere.
Is more barrier always better?
No: more barrier than needed costs more and can make recycling harder. It should be sized to the required shelf life.