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 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 will allow greater use of aseptically packaged food that requires no refrigeration. Time-temperature indicators and other smart packaging will help the consumer to better judge food quality and to avoid disposal of still-fresh food based on estimated date. Smart packaging will use self-reading indicators to say whether a product is fresh.

Let's review some barrier packaging applications to watch.

We'll begin in flexible barrier packaging with compostable cellulose film packaging of organic tea. NatureFlex NVR compostable cellulose-based material from Innovia Films has been chosen by Les Jardins de Gaïa to pack organic teas in individual sachets.

The film is manufactured using wood pulp sourced from managed plantations. The renewable or bio-based content of the film has been determined by ASTM D6866 and shown to be approximately 95 percent. It is a two-side-coated and heat-sealable film with an intermediate moisture barrier. The film, based on renewable raw materials, is certified as compostable in both industrial and home composting environments, and it is suitable for anaerobic digestion.

The film also provides:

  • Excellent barrier to gases and aromas
  • Resistance to oils and greases
  • Excellent transparency and gloss
  • Excellent dead-fold characteristics
  • Inherent anti-static properties
  • Wide heat-seal range (on both sides)

Innovia Films
Les Jardins de Gaïa organic tea packs (left) and NatureFlex NVR compostable film structure (right).

Next, in rigid barrier packaging, a seafood container is switching from metal to plastic. Bornholms has produced and developed canned fish products in Denmark since 1915. RPC Superfos has developed a series of four next-generation containers with an entirely new oxygen barrier solution.

Superfos manufactures sustainable high-quality injection molded plastic packaging for food and nonfood products. The coinjection-molded container has one oxygen barrier layer coinjected into its sidewall and a second barrier layer in the coextruded in-mold label applied during the coinjection molding process.

The container is a five-layer coinjection of polypropylene (PP)/tie layer/EVOH/tie layer/PP. The precise makeup of the in-mold EVOH/PP labels and label supplier are undisclosed. The container technology included identifying a suitable PP to withstand the retort for two hours at 117 degrees C. In addition to a three-year ambient temperature shelf life, container benefits include:

  • Lower packaging material costs
  • Lighter weight
  • Reduced carbon footprint
  • Higher filling speed
  • Stackability of empty containers (30 percent space savings)

For the consumer, the easy-to-open new container is resealable and also microwavable.

RPC Superfos
Bornholms co-injected seafood containers.

Continuing in smart packaging, MicVac microwave pasteurized ready meals have been developed. Chilled ready meals are a growing trend with today's busy lifestyle, increased single or two person households, increased disposable income and increasing westernization of food habits across major countries. These leading factors are driving demand for convenient meal options, especially ready meals.

A unique packaging concept for chilled ready meals provides an extended refrigerated shelf life greater than 30 days at 8 degrees C., thanks to microwave pasteurization technology by Sweden's MicVac.

In the process, raw food ingredients in a PP tray with a peelable polyamide (PA) or nylon/PP flexible film lidding is heat-sealed in place. Accurate control of sealing pressure/temperature ensures the lidstock/tray seal is strong enough to withstand internal pressure during pasteurization and consumer heating, yet remains easy to peel away when the heated food comes out of the consumer's microwave.

Just before the lidding material is applied to the filled trays, a custom labeler from European Labeling System GmbH punches a small hole in the lidstock and applies over the hole a unique MicVac valve. The servo-driven film transport of the SealPac tray-sealer helps deliver the accurate hole-punching and label-positioning that are required. SealPac GmbH developed a special application device for the patented MicVac valve on its tray sealers.

The patented MicVac valve designed so it can open and close multiple times opens to release internal pressure created as the food releases steam during cooking/pasteurization or reheating by the consumer.

The of contents of the tray are cooked/pasteurized in 4-10 minutes using microwave energy depending on the size of the food particulates versus 2-3 hours pasteurization in a steam oven or autoclave retort. As soon as the pasteurization process is completed, the trays are cooled, and the MicVac valve closes.

Steam trapped inside the tray condenses, causing a vacuum within the package. This causes the bottom of the specially developed FlexTray to curve upward while the lidding film is pulled down toward the food contents. Consumers are able to reheat the product in their microwave in only about three minutes, with the valve releasing the steam of the food once again.

The final result is a cooked, pasteurized and vacuum-packed product with excellent quality in taste, nutrition and texture, which can be presented attractively on the retail shelves — even vertically. MicVac has signed a cooperation agreement with Curwood/Bemis. The cooperation will make the unique MicVac technology for chilled ready meals available in North, South and Central America.

MicVac pasteurization process (left) and a microwave pasteurization-ready meal (right).

In conclusion, the principal function of packaging is protection and preservation from external contamination. This function involves retardation of deterioration, extension of shelf life, and maintenance of quality and safety of packaged food.

Packaging protects food from environmental influences such as heat, light, the presence or absence of moisture, oxygen, pressure, enzymes, spurious odors, microorganisms, insects, dirt and dust particles, gaseous emissions, and so on. All of these cause deterioration of foods and beverages.

Prolonging shelf life involves retardation of enzymatic, microbial and biochemical reactions through various strategies such as temperature control; moisture control; addition of chemicals such as salt, sugar, carbon dioxide or natural acids; removal of oxygen; or a combination of these with effective packaging.

Precise integration of the product, process, package and distribution is critical to avoid recontamination. The ideal packaging material should be inert and resistant to hazards and should not allow molecular transfer from or to packaging materials. Other major functions of packaging include containment, convenience, marketing and communication.

Containment involves ensuring that a product is not intentionally spilled or dispersed. The communication function serves as the link between consumer and food processor. It contains mandatory information such as weight, source, ingredients, and now, nutritional value and cautions for use required by law.

Product promotion or marketing by companies is achieved through the packages at the point of purchase. Secondary functions of increasing importance include traceability, tamper indication and portion control.

New tracking systems enable tracking of packages though the food supplies chain from source to disposal. Packages are imprinted with a universal product code to facilitate checkout and distribution control.