June 1999 -- Focus On
By: Steven Taylor
The story of the aseptic carton, from its roots in Europe in the 1940s to this decade and the dawn of the new millenium, is the story of an innovative technology, shaped and reshaped to meet the evolving needs of a diverse and growing customer base. It's little wonder that the Institute of Food Technologists has named the aseptic packaging process "the most significant food science innovation of the last 50 years."
This high-tech, innovative packaging solution outshines many others on the market by almost any standard. It delivers product with natural colors, vivid flavors, authentic textures and nutrient values nature intact - all while ensuring safety and shelf stability.
Long a staple outside the United States market because of its cost-effectiveness, the aseptic carton has steadily gained acceptance and market share in this country over the last fifteen years. And now the aseptic package is poised for explosive growth, especially in the U.S. foodservice sector.
Aseptic basics Aseptic cartons are a lightweight, multi-layer, energy-efficient example of minimal packaging. They combine high-performance materials with high-performance construction and high-performance features. The package is 70% paper (to provide stiffness and strength), 25% low-density polyethylene (to seal the carton liquid-tight), and 5% aluminum (to keep out light and oxygen). Together, these materials produce a carton that safeguards the aseptically processed product inside.
Products packaged in the cartons include a wide variety of beverages and liquid-based foods, such as juices, white and flavored milks, soups, sauces, broths, fruit toppings, syrups and chunky tomato products. In addition to the popular drink-box sizes, aseptically packaged products come in cartons that run the gamut from 150 ml to 2 liters. Although some new packaging formats have recently appeared on the market, aseptic cartons typically conform to the well-known block shape, which is favored because it permits easy stacking for more efficient storage.
But cartons and the products they contain are only a piece of the picture. The aseptic processing and filling technology is an equally important element of the story. Aseptic processing is a major advance over traditional canning. While canning and aseptic processing achieve the same level of product sterility, unlike canning techniques, aseptic processing sterilizes the product outside the package, using high-temperature/short-time (HTST) technology, which tailors the temperature (195° to 285°F) and time (generally 3 to 15 seconds) to place the least amount of thermal stress on the product. Retort and hot-fill canning processes, on the other hand, take minutes, sometimes as long as 50. Typical HTST processor types include tube-to-tube, plate sterilization, steam infusion and steam injection. Depending upon product type and package size, flow rates can range from 10 to 50 gpm.
Aseptic packaging sleeves are formed into cartons and sterilized in the filler with a hot hydrogen peroxide vapor. Once the vapor is evaporated with hot, sterile air, the sterilized package is filled with the sterilized product, both are cooled to ambient temperature, and then sealed within a sterile zone. This results in products (even traditionally perishable ones such as milk) that can remain unrefrigerated and shelf stable for months at a time without preservatives. Aseptic cartons mean no refrigerated trucks, no special warehouses and no kitchen freezer storage.
Environmental profile In today's increasingly environmentally conscious world, it's worth noting that the source reduced, energy-efficient aseptic carton is among the most environmentally friendly packages on the market today. In research conducted for the EPA, Boston-based Tellus Institute reports in its study of single-serve packaging that "the recycled aluminum can and the aseptic package have the lowest environmental costs."
In 1996, the aseptic package won the Presidential Award for Sustainable Development, the first package ever to win this coveted U.S. environmental prize. At a White House awards ceremony, Vice President Al Gore praised the aseptic packaging industry for its "outstanding contribution to a sustainable future." Moreover, the carton is being recycled in over 10 million homes across the United States, a number that grows steadily every year.
Industry innovations The first aseptic cartons had to be opened by tearing carton flaps or using kitchen shears. In response to customer demand for a convenient, easy-to-use reclosable fitment, SIG Combibloc introduced the first reclosable top designed for aseptic cartons, the combiTop®, which makes opening, pouring and reclosing large, multi-serve cartons a snap. Made of polypropylene, and attached to the carton downline of the filler using hot-melt glue, the combiTop was designed for viscous fluid products, without particulates.
In order to make v-notch, bend-and-tear and other perforated openings more convenient, in 1997 SIG Combibloc unveiled a laser-cutting system, which allows for a level of precision cutting that traditional perforation openings cannot match. Laser-cut openings are very easy to tear, but in no way compromise the integrity of the carton. The company also put the first particulate fillers in the marketplace.
Aseptic cartons are shipped to processors in preprinted web rolls or individual sleeves. At SIG Combibloc, the critical back seam for the carton is made in their manufacturing plant under controlled conditions. Automated, high-speed finishing lines crease and cut the carton blanks and form the back seam, leaving no exposed edges, forming a superior oxygen barrier. The packages are folded and top-sealed above the product line to create and adjust, but never totally eliminate, carton head space. Head space allows for a clean seal; that is, no product is trapped in the seal area. The actual amount of head space varies by package size and product type. Another advantage is that head space allows the fillers to fill cartons with particulates easily, efficiently and at rated speeds.
Filling technology development Aseptic carton fillers in the United States currently allow for the processing and packaging of high-acid foods with particulate matter that is 15x15 mm or smaller, such as chopped tomatoes and fruit toppings. Low-acid, particulate foods, such as soups and stews laden with chunks of potatoes, mushrooms, and vegetables, will begin to appear in the U.S. market once processes and procedures have been decided by the FDA.
But U.S. aseptic packaging customers are demanding more of the aseptic package and process. Specifically, users of aseptic cartons want larger food particulates, higher viscosity products, a greater percentage of particles by weight, multiple products on a single filler, and two-phase filling - liquid and slurry, for example. SIG Combibloc has introduced a new generation of filler meeting such customer-driven requirements that is currently in use in France.
The company's first generation of food fillers, introduced in 1985, could handle 8 x 8 mm particulates. Within three years, a refinement of that filler had increased particulate size capacity to 15 x 15 mm. The second-generation filler, which made its appearance in 1993, was redesigned so that product components (noodles and broth, for example) could be processed separately but simultaneously (ensuring that the processing times and temperatures were perfectly suited to the component) and filled with two shots into the carton. And today, the third-generation filler, also a two-shot machine, can handle particulates with dimensions up to 20 mm edge length and viscosity up to 20,000 mPas. Generation three brings aseptic filling machines to a new level of sophistication and ease of operation. This technology is available for cartons from 150 ml to 1 liter.
The pay-off for aseptic carton customers is that they have a range of sizes, opening features, and filling capabilities to meet a variety of needs.
Pushing the envelope Larger sizes, innovative opening features, and advanced filling systems are all important trail markers on the path the aseptic carton has taken. The aseptic industry is committed to continuing its practice of pushing the technology envelope to provide the liquid food and beverage packaging solutions that customers require. Research and development have always been important, and that is more true now than ever. The aseptic package - the intelligent package - will continue to evolve and reinvent itself in response to market demands, which makes it an exciting time to be in this industry.
Steven Taylor is vice president of engineering for SIG Combibloc Inc., Columbus, OH. He holds graduate and undergraduate degrees from Purdue University. Founded in 1983, SIG Combibloc Inc. is a supplier of aseptic carton filling systems and packaging to North, Central and South America. Its parent company, SIG Swiss Industrial Company Holding Ltd., is headquartered in Neuhausen, Rhine Falls, Switzerland. SIG Combibloc's customers include Lyons-Magnus, Tree Top, , Kaiser's Companies, The H.R. Nicholson Company, Westbrae Natural Foods, Farmland Dairies and Jugos del Valle.
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