Over the last 10 to 15 years, more low- and high-acid products have been processed in ways designed to kill bacteria and extend the life of foods and liquids. Retort-style thermal processing, chilling and refrigeration steps and the use of preservatives remain the most common routes to produce shelf-stable foods and beverages in the US. But emerging trends, economic and performance benefits, and new equipment developments in aseptic technology are making this sterilization approach worth another look.

The latest advancements are designed to handle sensitive, low-acid products. They include a new fill/seal unit that provides low-volume production with wide package configuration choices; an aseptic bag-in-box system that delivers three times the production speed with package-style flexibility and machine compactness; and an aseptic blower for PET that sterilizes preforms and is coupled to an aseptic filler.

“There are several consumer- and processor-driven movements that are dovetailing into a more favorable environment for the use of aseptic packaging and technology in the US. Consumers are looking for more natural foods or products containing fewer preservatives, and they’re more willing to purchase products in packaging they can place on a pantry shelf for longer periods without fear of spoilage,” says John Panaseny, president of OYSTAR USA.

At the same time, food and beverage plants and retailers are looking to reduce energy costs associated with the production and handling of chilled or refrigerated products, namely by exploring packaging and processing options such as aseptic that can pull certain products from the cooling chain. “It costs more money to stock a product in the refrigerated section of a store. With aseptic packaging, the product does not need to be kept refrigerated and can still attain a longer product life,” says Brian Tuel, vice president of sales and marketing at A&B Process Systems.

Removing a product from the entire cold distribution chain—from production in a refrigerated plant, transportation in a refrigerated truck to placement in the refrigerated section of the store—is opening new markets for shelf-stable products and the techniques to make them. In addition, aseptic packaging is a viable alternative in countries and territories without well-established cooling distribution systems.

Products thermally sterilized using a retort process—where the container is filled with product, heated and cooled together in a sterilizing step—is less energy and time efficient than more modern technologies, says Tuel. “Heating and cooling in a retort system can take some time to achieve, and if the cooling step isn’t completed, the food can continue to cook in the can. This can result in a loss of flavor, color or appearance.”

Aseptic processes sterilize the product and the package separately, unlike a retort process where the product and package are treated together. Plus, with aseptic processes, less expensive packaging materials such as plastics, including polypropylene, polystyrene or polyethylene, can be used.

“We are working with a large processor looking to move its entire product line from glass packaging to aseptic plastic packaging, primarily for the savings gained from transporting a plastic container versus a glass container,” says Panaseny. A lighter plastic container means more packages per truckload for the customer, he adds.

Aseptic is considered a thermal treatment, since it tends to use steam heated to 140°C. With it, the product is sterilized in one space, while the packaging is sterilized elsewhere. Then, the components are put into a machine within a sterile environment where the sterilized package is filled with the sterilized product and sealed within the sterilized chamber. Aseptic processes control bacteria to >log 4, depending on the microorganism being expunged.

Processors can sterilize an aseptic package with steam, vaporized hydrogen peroxide, radiation/UV or infrared or with other approaches such as high pressure or autoclaving, although these systems may drive up the cost. Aseptically sterilized product travels inside a sterile tunnel that is over-pressurized with sterile air to prevent bacteria from entering. Retort is a batch method, while aseptic processing is typically a continuous method, allowing for higher production rates.

Lower volume, higher flexibility

Form/fill/seal machines are commonly used where the large-volume production of aseptic consumer packages is required. However, the equipment does not provide a high degree of packaging flexibility, says Panaseny.

To address this problem, OYSTAR is developing a new line of aseptic machines for smaller processors that want aseptic packaging technology capable of handling more types of packages.

Form/fill/seal units like OYSTAR’s Hassia line use rolls of polymer material that are heated and thermoformed in the machinery unit, then indexed to the filling zone within the unit for filling and sealing. The unit uses a special system of indexing pins  to pull the sheet through the sterile zone from thermoforming

to filling. Competitive units use a chain system to move the product, which can be an issue since lubrication on the chain can compromise the sterile zone in the machine.

The Hamba fill/seal machine produces aseptic packages from premade cups. The technology helps smaller product volume processors move away from food preservatives while retaining product shelf life and freshness. “There has never before been a premade

aseptic cup for low-acid products on the market. A fill/seal machine is highly flexible, allowing a wide range of shapes to be used [round to square may be possible] simply by changing out a carrier plate,” says Panaseny.

Bakoma Sp. z o. o., Poland’s largest dairy foods producer, installed the new OYSTAR Hamba Flexline FL 8/8 CA unit to aseptically fill and seal preformed dairy cups with 90-400g of product at rates up to 38,400 cups /hour. The cups are cleaned with ionized air, sterilized with peroxide and dried with sterile air. Three different dosing devices provide product flexibility. The adjustable sealing heads are designed to reliably seal 16 cups (with lids) per cycle. Filling and sealing operations occur intermittently using the premade shapes. OYSTAR’s Hassia division shared its 30-plus years of know-how in aseptic packaging with the OYSTAR Hamba division to produce the fill/seal units.

OYSTAR Hassia’s aseptic form/fill/seal technology is used in the production of nonrefrigerated, single-serve coffee creamers, puddings in a cup, baby food and cheese sauces. There are more than two dozen applications in the US, and interest is growing, says Panaseny. The company has developed a new OYSTAR Hassia model capable of producing flexible pouches aseptically as an alternative to rigid packaging. OYSTAR also produces models that provide ultra-hygienic, but not aseptic, levels of bacteria control. These systems can be used by firms outside the US that are not bound by FDA requirements for sterility levels.

With the OYSTAR Erca form/fill/seal model, the plastic roll is sterilized offsite and covered with a peelable cover layer. Prior to forming in the unit, the cover layer is removed to reveal the sterilized layer underneath. This approach eliminates the need to steam or chemically treat a package.

Speed in the bag

Introduced at last year’s PACK EXPO, the new Sealed Air high-speed bag-in-box system delivers bag filling speeds three times those of standard aseptic bag-in-box fillers.

The IDC/Cryovac SpeedFlex bag-in-box unit, developed through an alliance between Sealed Air and International Dispensing Corp., a supplier of bag fitment technologies, processes four- to 20-liter formed bags into bag-in-box packages at rates up to 30 bags/minute, says Myra Foster, executive director, global fluids sector, Sealed Air food care division. The unit sterilizes with a combination of steam and hydrogen peroxide.

The IDC/Cryovac SpeedFlex system delivers a packaging solution along with packaging equipment for aseptic processes and features efficient changeover capabilities that minimize downtime. The solution targets shelf-stable applications for dispensing or opening and reclosing bulk packages for foodservice markets or other end-users. The unit is FDA accepted for the aseptic packaging of low-acid and beverage products, including flavorings, fruit purées, juices, sauces, smoothies, ice cream mixes, tea, coffee and syrup used in fountain beverages.

Foster says the bag filler’s increased production speeds and overall improved operational efficiency are the results of updated engineering design. For example, the mechanics of the rotary filler were optimized to achieve the increased speed, which also led to a reduction in the footprint of the unit. The filler can be integrated with any existing aseptic system.

Sealed Air says its line of vertical form/fill/seal units, introduced in the US two years ago, is expected to record its first commercial installation and startup in the US this year. It can produce shelf-stable pouches ranging in size from two to six liters. Sealed Air also offers a Pro-Aseptic horizontal form/fill/seal unit, introduced in Europe last year, that produces flexible standup pouches.

Germ-free PET preforms

Weight savings (material cost savings) is a significant reason for the development of the GEA Procomac aseptic blow fill system that simultaneously sterilizes the internal and external surfaces of a PET preform. It consists of a traditional heating oven with a preform sterilizer, sterile blower and aseptic filler, says Flavio Salvadori, sales director for GEA Procomac S.p.A. in Italy.

The preform is warmed in the oven and sterilized by hydrogen peroxide in a single step to avoid cross-contamination. “This is similar to the well-known wet PAA technology where sterilization of a bottle’s internal and external areas are carried out at the same time,” says Salvadori.

Aseptic blowing, filling and capping operations are performed in a sterile zone called the microbiological isolator, a section where every component, including piping into and out of the zone, is sterilized. “We physically separated the mechanical machine parts from the sterile zone and then designed every component in the sanitary zone to be cleaned with foaming agents and sterilized with vaporized hydrogen peroxide,” says Salvadori. The unit is pressurized with sterile air and uses a redundant HEPA filter station to obtain a class 100 sterile area.

Once sterile, the preform enters the sterile area of the blower, undergoes stretch-blow molding and is filled aseptically, explains Salvadori. “The savings in terms of PET usage are clear, due to the possibility of lightweighting the bottles further,” he says. The ABF unit has passed low-acid microbiological validation tests and is suitable to fill milk and milk-based products. The unit can produce one-liter bottles in six to 24 cavities at rates from approximately 12,000 to 48,000 bottles per hour.

Range of technology

Bosch Packaging Technology dosing systems and filling nozzles enable flexibility and filling precision in the production of single-serve packaged foods. The company became a single-source supplier of liquid and viscous food packaging for aseptic and other hygienic filling applications through the 2012 acquisition of Ampack, a maker of cup and bottle filling units.

The acquisition has strengthened Bosch’s portfolio of filling and packaging machines in the area of various hygienic levels, different pack styles and research and development, says Santy Witarsa, director of sales, marketing and product management for the liquid food business unit of Bosch. The company forms cups in line with its thermoforming process, but can also produce premade cups and bottles. It also produces dosing systems and peripheral machinery.

Custom, for the customer

Although A&B Process does not manufacture its own line of aseptic equipment, it provides services to fabricate a custom line and supplies a range of components, including mix-proof aseptic valves, automated valve system manifolds, piping, tanks and a range of other components, that boost production,

trim changeover times and/or eliminate human contact with the product. A&B Process is enhancing a CIP skidded system it developed, with an eye toward its use in aseptic applications, says Tuel.

“New technologies of all types are helping to further aseptic programs in the US. An increase in aseptic applications will challenge American perceptions as to what ‘fresh’ means. We are accustomed to looking at an expiration date for freshness. In countries where aseptic technologies are embraced, consumers routinely go to the store shelf for their dairy products,” says Tuel.

Extended shelf-life applications are a potential boon for food plants too: They could eliminate the need for plants on both the East and West Coasts to serve customers in different markets. Shelf-stable foods can reduce distribution points or alleviate time-to-market pressures while still ensuring fresh products.

For more information:

Brian Tuel, A&B Process Systems Corp., 715-506-0465, btuel@abprocess.com
Santy Witarsa, Bosch Packaging Technology, 49 711 811 57477, santy.witarsa@bosch.com
Flavio Salvadori, GEA Procomac Engineering, 39 0521 839 490, flavio.salvadori@gea.com
John Panaseny, OYSTAR USA, 732-343-7610, jpanaseny@oystarusa.com
Myra Foster, Sealed Air Food Care Division, 201-791-7600, myra.foster@sealedair.com