Download this free, 140-page Flexible Packaging Playbook jam-packed with strategies for success, best practices, and pitfalls to avoid.  Learn more »
Glenroy invites you to download this playbook.
Article |

Films let produce breathe comfortably

Passive controlled atmosphere technology that lengthens the shelf life of fresh-cut produce takes many forms, as these three FPA award winners demonstrate.
2 Microperforations in the film are invisible to the naked eye3 OTR of these films can be tailored to meet the requirements of the produce being packed1The label is a breathable membrane permiting a gas exchange through the package that lets apples respire

"When the apple is sliced the carrot shredded or the broccoli cut a cascading set of physiological and biochemical reactions are initiated which will cause a rapid deterioration of the product." William Romig EPL Technologies MAPack '95 Three fresh-cut produce packages each using different ways to retard Romig's "cascading set of physiological and biochemical reactions" are winners of the Flexible Packaging Association's 1995 Top Packaging Awards. (For a look at other FPA winners see pages 22 41 and 64.) Though each solution is different all involve breathable films and passive controlled atmosphere technology. In other words they extend shelf life by limiting oxygen supply slowing the live product's respiration rate and thus retarding spoilage. One of the winning packages is from Met West Agribusiness a grower/packer in Del Rey CA (see PW October '95 p. 2). Its 1-lb portions of Sunmet sliced apples (1) in zippered reclosable bags reached store shelves last September. Refrigerated shelf life is 12 days thanks to the pressure-sensitive Fresh Hold® label developed by Fresh Valley Technology (Salinas CA) and converted by Avery Dennison (Monrovia CA). The label is a breathable film membrane that's applied over a precisely cut hole in the bag. It permits the release of carbon dioxide and the entry of oxygen to create an internal atmosphere where the apples can respire and stay fresh. Citric acid sodium erythorbate and calcium chloride are added to keep the apples from browning. The premade bags a blend of ethylene vinyl acetate and linear low-density polyethylene are flexo printed in four colors by Maine Poly (Greene ME) and supplied on wickets. Met West fills and heat seals them semi-automatically. The apples retail for about $3. Gone but not forgotten Another FPA winner is the package that was marketed by Andy Boy Associates of Parsippany NJ. They too found a way to extend shelf life by means of a breathable film. And even though the produce company went out of business in January its innovative and award-winning packages are worth examining (see story on Andy Boy Soups page 58). Shown here are Andy Boy Broccoli Florets and San Francisco Stir Fry (2) just two of the 13 items that made up its line of fresh-cut produce. They were packaged in a 1.18-mil oriented polypropylene from James River Corp. (Milford OH) that's microperforated with just the right amount of minute holes. Invisible to the naked eye they allow the produce to respire at the proper rate. The number of holes is adjusted to meet the varying respiration rates of each variety of product. Depending on the variety shelf life can be extended for days or weeks. The bags are also anti-fog treated. Salad mixes and other vegetables have been packaged in breathable films tailored to their respiration rates for a couple of years. So why the need for something as exotic-sounding as "microperforation?" Because says James River most films used to pack fresh produce are too impermeable for high-respiring products like broccoli cauliflower carrots and cut fruit. Downgauging films to increase permeability is rarely the solution since it makes machineability problematic. This dilemma was recognized by Sidlaw Packaging (Bristol England) in the late 1980s so the firm developed a microperforation process that received two United Kingdom patents. It then created a global trademark P-Plus(TM) for its technology applied for overseas patents and began to seek international licensees. In 1993 James River acquired North American rights and a year later it began producing microperforated films at its San Leandro CA plant. As James River's Ted Frey reported in a paper last October several P-Plus applications have been commercialized primarily in the oxygen transmission range exceeding 500 cc/100 sq"/24 hrs. Frey also addressed the question of whether the microperforations could become a pathway for microorganisms. "Sidlaw commissioned in 1991 a microbiological study by the Campden Food and Drink Assn. which addressed external contamination" Frey reported. "The Campden report concluded that such ingress would be 'extremely rare.' Fundamentally contamination caused by poor sanitation prior to packaging presents a far greater risk than the potential for P-Plus holes to create a dangerous microbiological situation." No perfs in PD 900 family While James River went the microperf route for heavy breathers like broccoli and cauliflower Cryovac (Duncan SC) pursued a strategy based on resin formulation and process development for its PD 900 family of films. Mann Packing of Salinas CA uses the PD 960 variety for its FPA award-winning Rainbow Salad and Broccoli Wokly packages (3). A proprietary coextrusion based on an unnamed polyolefin the Cryovac film can be as thin as .6 mils. Cryovac claims that represents "up to" a 75% reduction from what it calls "existing films" yet it's still rugged enough to run on high-speed form/fill/seal equipment. Oxygen transmission rates run from a broccoli-pleasing 1 cc/sq"/24 hours down to 225 cc/sq"/24 hours which is more suitable for carrots and onions. It's also available in the form of pre-made bags and with an anti-fog feature. The Mann packages shown here produced from rollstock on a vertical form/fill/seal machine were flexo-printed in eight colors by Cryovac. Further information is difficult to come by; a Mann spokesperson says the firm is "not comfortable" talking about the package. Expect to see more of these extended shelf life produce packages in the future. Industry observers predict that fresh-cut produce will constitute 25% or 40 billion lb of U.S. produce consumption by the year 2000.

E-Book Special Report
Total Cost of Ownership
Sign up to receive timely updates from our editors and download this E-Book Special Report to learn how to calculate the true Total Cost of Ownership (TCO) of your packaging machinery.


Don't miss intelligence crucial to your job and business!
Click on any newsletter to view a sample. Enter your email address below to sign up!
Each newsletter ranges in frequency from once per month to a few times per month at most.