Note: This is the third article of a three-part series covering plastics in barrier packaging (1) trends, (2) material/process advances and (3) applications.

Barrier developments in food packaging are expected to greatly help reduce food waste to better feed a growing world population. Approximately 1.3 billion tons — or one-third of the food produced around the world each year is lost or wasted on its way from the farm to the fork. In industrialized countries, 210 to 255 pounds of food still fit for consumption per person is simply thrown away each year.

With limited natural resources, it is more effective to reduce food losses than to increase global food production. Barrier packaging advances in will allow greater use of aseptically-packaged food that requires no refrigeration. Time-temperature indicators and other smart packaging will help the consumer better judge food quality, to avoid disposal of still-fresh food based on an estimated date. Smart packaging will use self-reading indicators to say if a product is fresh or not.

Let's take a look at some examples of emerging plastic barrier-packaging applications.

After successful implementation of the "It'sFresh!" innovative ethylene-management technology to extend the shelf life of fresh berries, Marks & Spencer (M&S) is adopting the technology to extend the shelf life of other soft fruits such as nectarines. M&S was the first retailer to use this ethylene-absorption technology to extend the shelf life of fresh fruit and decrease produce spoilage.

M&S launched the use of the new ethylene absorption system in their retail fresh strawberry packages two years ago and found its use reduced waste by 4 percent. This is equivalent to 40,000 one-pint packs of strawberries. The fruits also tasted fresh longer.
Marks & Spencer stone fruit ethylene-absorber packaging.

A food-grade nonwoven strip coated with a patented mixture of high-tech minerals and clays (palladium and zeolite) offers 100 times greater ethylene absorption capacity compared other known ethylene absorption materials. The effectiveness of the It’sFresh! ethylene remover has been confirmed in an independent trial conducted at the University of Greenwich by East Malling Research and the Natural Resources Institute.

Positioned at the base of the package, the 8 cm by 4.5 cm strip does not affect package recyclability. Any package incremental cost is more than offset by produce quality/shelf life improvements and reduced distribution costs.

Following Marks & Spencer's lead, Tesco became the first retailer to test the packaging on tomatoes and avocados. The company says the strips could save 1.6 million packs of tomatoes and 350,000 packs of avocados a year.

Continuing with a second application, there is a recyclable, biodegradable co-injected fish package under development. The "Thinfish" project is looking to develop high-barrier, long-life, low-cost, recyclable, biodegradable packaging through co-injection for noncooked seafood packaging applications.

Thinfish, a continuation of research carried out in the FP7 (the European Union's Seventh Framework Programme) project Cobapack, is being conducted by a consortium including thermoplastic injection molder Criimpla SL (the project leader), AIMPLAS (the Spanish Instituto Tecnológico del Plástico), ANFACO (the Spanish National Association of Fish and Seafood Canning Manufacturers-Technological Centre for the Preservation of Fish, Seafood and Aquaculture Products) and Akumplast JSC, a private Bulgarian plastics manufacturer.

Main innovations proposed in Thinfish project (top); PP/starch three-layer sandwich structure (bottom).

Most currently-used barrier multilayer packages are obtained by a co-extrusion process followed by thermoforming. The manufacture of these packages often leads to considerable scrap production and design limitations (neither complex forms nor uniform thickness).

The noncooked seafood application includes nonthermally-treated marinated, smoked and spicy fish packaged products in particular anchovy, herring and fish salads. Approximately 2 billion packages of noncooked fish are marketed annually using a wide range of packaging materials such as metal, glass or plastic. Manufacturing the new package in a one-step co-injection process minimizes scrap losses, saves energy consumption, allows broad design flexibility and reduces waste disposal costs

The innovative package has a sandwich structure of three layers:

  • Two exterior layers made of polypropylene (PP), a recyclable plastic with high moisture barrier
  • An inner layer made of starch extracted from wheat that provides effective oxygen-barrier resistance and is completely biodegradable when totally dissolved in water

The destructurized wheat starch is totally soluble in water, which allows the complete separation of the PP package skin from the starch core. Thus the package's PP skin is 100 percent recyclable, and the dissolved starch can be used as fertilizer.

Finally, let's take a look at recent novel rigid barrier containers. New ready-to-drink plastic wine glasses recently introduced by Cefour Wine & Beverage AB of Sweden make use of a transparent multilayer PP/EVOH/PP (polypropylene/ethylene vinyl alcohol/polypropylene) sheet supplied by RPC Cobelplast to create the "Easy Wine Glass."

RPC Cobelplast
Easy Wine Glass.

The EVOH barrier layer prevents oxygen ingress to help preserve freshness and quality of the wine for up to 10 months. The prefilled 187.5-milliliter single-service glasses are particularly suitable for outdoor events where the use of glass is not suitable for safety reasons.

RPC Cobelplast
Heinz baby food tub.

Heinz is also using PP/EVOH/PP barrier sheet supplied by RPC to thermoform new plastic baby food tubs with snap-on lids, first introduced in 2012 for market testing purposes and now fully commercialized. The tubs are user-friendly and microwavable for convenient reheating. Their shatterproof properties also enhance consumer safety.

The new packaging weighs 85 percent less than the traditional glass-jar-and-metal-lid packaging. The barrier sheet material delivers effective protection against oxygen ingress, providing an ambient shelf life of up to 12 months. The new Heinz baby food package is a recipient of the Italian Institute of Packaging award, Oscar dell'Imballaggio.