Eric DesRoberts

January 30, 2014

3 Min Read
Modified atmosphere packaging needs special care for recycling

I was recently cleaning out my tennis bag and discovered an impressive collection of old tennis balls and ball canisters from last fall. As a member of the packaging community, my first question was, "How can I keep these out of the landfill?"

The balls were no problem. Many of my coworkers have dogs, and the hardwood floors in my apartment are benefitting from297101-SPC_logo.jpg

SPC logo

the new leg covers on the bottom of my chairs. The canisters are a different story. With three different plastic components and a metal seal, I knew they would be an adventure.

I remembered an article about canister recycling at the U.S. Open in which individuals were separating components by hand to limit recycling contaminants and enable each component to be recovered. Most of the canisters contained a PET body, an LDPE lid/cap, an aluminum seal and an unmarked full-body sleeve. Utility knife in hand, I was eventually able to separate and recycle all materials but the sleeve. But why was the container made this way?

Historically, steel, aluminum and paperboard containers were used to store tennis balls, but by the mid 1980s, plastic canisters were gaining significant market share. A majority of tennis balls used in match play are pressurized and therefore stored in canisters that are also pressurized and hermetically sealed. Pressurized tennis balls are filled with nitrogen or compressed air and stored in pressurized containers to prevent the balls' internal pressure from diffusing. While some of the earlier canister options would likely meet these performance requirements and possibly have less complex end-of-life options, today's plastic canisters are a high-performance, cost-effective solution.

The pressure sensitivity issues and the use of nitrogen point to the parallels between tennis balls and foods packaged in modified atmosphere packaging (MAP). Flushing food packaging with a mixture of high purity nitrogen, oxygen and carbon dioxide is commonly used to reduce product spoilage and help extend the shelf life. Carbon dioxide inhibits bacteria and mildew growth, and is often regarded as the most important component of the mixture.

However, fats and water readily absorb carbon dioxide and can lead to changes in taste and moisture content. Nitrogen is used to displace oxygen, which supports aerobic microorganisms and decay, but the presence of oxygen, used in controlled quantities, often helps maintain product coloration and inhibit anaerobic microorganism growth.

While the MAP used in food products and tennis balls greatly differ, many of these packaged goods contain non-recyclable components or are made in a way that makes them not widely recyclable. Considering the food often packaged in MAP (such as raw meats, fish, convenience products, prepared fruits and vegetables), food contaminated boards and trays, thin films and wraps, and multilayer and/or multi-component substrates all pose potential problems in the recycling stream and have limited end-of-life options.

This is another example of the tradeoffs and interactions between products and packaging. The high-performance, cost-effective solutions prevent the products from going to waste but, in doing so, generate packaging waste. While innovative MAP solutions showcase the value of packaging via reduced production costs, product preservation and extending shelf life, we also need to push for more innovation toward managing the end of life for these materials.

Eric DesRoberts is a project associate for GreenBlue's Sustainable Packaging Coalition.

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