Aseptic processing and packaging still struggles to achieve anything more than a lukewarm embrace in the US market, with two-steps forward, one-step back characterizing the technology’s progress over the last three decades.
Part of the problem is the lack of a clear quality advantage over well-established and less expensive alternative technologies, such as hot fill for acidic beverages and retort for solid foods. Difficulties in validating commercial sterilization of pumpable foods with particulates also play a role in retarding aseptic’s progress. However, dairy-based beverages in PET containers have shown promise, and a 2009 study by Gordon Bockner, president of Business Development Associates, projected solid growth, as low-acid beverages such as nutritional drinks, ready-to-drink teas and other products convert to aseptic.
Yet repeating the pattern of the past, the rosy forecast is on hold, pending resolution of patent-infringement litigation involving a copacker and two equipment suppliers (see related story on page 66).
Plus, package aesthetics are a driver in retail sales, while aseptic’s real potential resides in cost reductions in distributing perishable products. Business-to-business sales of processed foods are where aseptic is having its greatest impact, and that likely will remain the case for the near term.
North Carolina State University (NCSU) staked out a leadership role in aseptic processing two decades ago, and the school’s R&D work continues. Last year, USDA awarded the school a grant “to develop the methods and study process safety validation of high acid and low acid food products containing discrete particulate ingredients,” according to Dr. Josip Simunovic, a research scientist at NCSU and cofounder of Raleigh, NC-based UltrAseptics Inc. The first commercial application of the continuous flow microwave sterilization process developed by NCSU was four years ago at Yamco LLC in nearby Snow Hill, NC.
Seven sweet potato growers established Yamco to process shelf-stable sweet potato purée. The low-acid product is aseptically filled in 6-, 55- and 300-gallon bags, drums and totes weighing up to 2,300 lbs. Much larger payloads are beginning to move through a global network using food-grade intermodal tanks holding up to 6,340 gallons of sterile product. Even larger quantities of orange juice have been transported in ocean-going tankers for decades, but a joint venture called AsepTrans takes the concept further by coupling the containers with a double block-and-bleed system that maintains sterility over multiple product removal cycles. The container essentially serves as a bulk storage unit that eliminates the disposal costs of drums and sterile bag liners and adds flexibility in accessing tank contents.
AsepTrans is a joint venture between Hawaii Intermodal Tank Transport and Rochester, NY-based JCS Process and Control Systems Engineering, which developed the double block-and-bleed transfer technology a decade ago. “This is a new application of old technology,” explains Phil Frechette, president of JCS. “This is the way to go for anybody who has large volumes of ingredients,” particularly those that must be sourced from specific regions in the world. An example is coconut water, a wastestream in coconut processing that is enjoying success as a nutrition and immune system-boost beverage. The low-acid water is susceptible to oxidation and spoilage, and a high-temperature, short-time process is necessary to retain its nutritional value. By using the AsepTrans system, a company in the Caribbean is able to distribute the water to multiple distribution points in the continental US without compromising quality while eliminating the handling costs of drums and liners, which can be significant, according to Frechette.
Last year, a client began shipping not-from-concentrate orange and pineapple juice from Florida to Europe without refrigeration, he adds, and in February, a low-acid liquid product embarked from Sri Lanka for a four-week trip to California in one of the tanks.
Beyond steam heat
Most innovation in aseptic revolves around filling and packaging, but scientists continue developing processing systems that can improve energy efficiency and temperature control. One example is a system that combines resistance heating and magnetic induction (MI) being developed by Geneva, IL-based Prove It LLC. A second-generation system is being built in Prove It’s suburban Chicago lab. Major food manufacturers and equipment suppliers are monitoring developments as the system inches toward commercial scale-up.
Steam is the heating medium for many food and beverage processes, and while steam is regarded as a very efficient heat-transfer tool, efficiency plummets when boiler losses are factored in, points out George Sadler, Prove It’s chief technology officer. Resistance heating, on the other hand, “is close to 100 percent efficient in converting electricity to heat,” he says. “What it is lacking is temperature control.” Heating elements are clad in ceramic, limiting the surface heating area and retarding the speed of temperature adjustments, resulting in bake-on and scorching.
Prove It’s design places metal elements within a dielectric tube, producing rapid come-up in temperature before a switch to magnetic induction is made for final polishing. Magnetic induction’s response is limited only by the sensitivity of the thermal coupler: Within seconds of receiving the temperature signal, temperature can be adjusted. Strict temperature control not only makes the process more efficient, it lowers the set point manufacturers can use to ensure microbiological sterilization, resulting in less impact on nutritional content and flavor.
Testing of a 10 kilowatt prototype system was done in collaboration with Pilot Aseptic LLC, which operated in space adjoining Prove It’s office. The food scientists at Pilot Aseptic were, like Sadler, former workers at the National Center for Food Safety and Technology, an R&D lab where basic research on high-pressure processing, pulsed electric fields and other novel processes has been conducted. Sadler likened the prototype to “a tinker toy compared to a commercial unit,” so a scalable prototype is being built. Given how entrenched steam cooking is, he doesn’t expect MI/resistance heating to supplant it any time soon, but alternatives to processes powered by fossil fuels will eventually become the norm, not only for aseptic but also brewing and other food processes, Sadler predicts.
Microwave heating is farther along the commercial-acceptance trail. The technology received a viability boost in January when Industrial Microwave Systems (IMS) forged a manufacturing partnership with AMTek (Applied Microwave Technologies), a manufacturer of magnetrons and other microwave components based in Cedar Rapids, IA. While IMS recently shut down its facility in Morrisville, NC, and its website went dark, General Manager Bob Vorhoff insists operations weren’t affected. “We never really shut down,” says Vorhoff, who is overseeing the transfer of business operations to Harahan, LA, where parent company Laitram is based. “By partnering with AMTek, we’re able to take advantage of their volume-manufacturing capabilities.”
Another microwave technology that resembles retort but delivers the rapid heating of aseptic processes is approaching commercialization after a decade of R&D at Washington State University. Known as MATS (microwave assisted thermal sterilization), the process relies on a series of magnetrons that bombard in-container food as it is conveyed through a pressurized water bath. FDA has accepted the system’s mathematical model for validating commercial sterility (see “Move over, retort,” Food Engineering, February 2010).
The commercial transition is being managed by Food Chain Safety, with a strong assist from a consortium of OEMs and food companies, including Kraft, Hormel and Masterfood. One of those firms is the likely landing place for the first industrial line, which will be able to produce 150 units a minute continuously, with about a seven-minute dwell time. “We have a pile of parts” and an engineering design currently, CEO Rob Wilson says, but he expects the line to be installed by year’s end. “So far, we’re on track.”
In January, the company announced the formation of MATSpack LLC, a partnership with Printpack, an Atlanta packaging firm. MATSpack will develop the nonmetallic packaging that will maintain sterility post processing.
Wanted: more container options
Filling sterile food into containers that aren’t cartons remains a challenge. Seven years after Campbell Soup introduced Select Gold Label soups in 500ml Combibloc cartons, SIG Combibloc remains the only aseptic carton that is FDA approved for liquids with particles up to 15mm, according to Jerry Henry, business development director at SIG Combibloc USA, Chester, PA. Unlike competing systems, SIG’s cartons are sealed on the bottom prior to filling, minimizing the possibility of product contaminating the sealing surface and compromising sterility.
Marketers believe the aseptic carton’s association with children’s drinks has slowed the technology’s US growth. Manufacturers overcame the challenge of in-line sterilization of plastic bottles, with hydrogen peroxide the most widely used sterilant. GEA Procomac fillers use peracetic acid in liquid form, and Nestlé began using the technology in 2009 at its Anderson, IN facility with PET bottles. Other sterilization options exist, including a high-power electron-beam system from Shiboya Hoppmann, but peroxide and peracetic acid are the only FDA-approved sterilants.
But Procomac’s system is expensive—Nestlé paid more than 10 million Euros ($13 million US) for its low-acid filling line, according to GEA Group—and most manufacturers opt for peroxide-based lines. They also see more potential in PET bottles than HDPE because of PET’s clarity, according to Business Development’s Bockner. Until litigation involving these systems is resolved, Bockner says the potential for growth in new product introductions involving low-acid liquids in PET containers has been interrupted.
Not so, insists Pete Schweitzer, sales engineer with Stork Food & Dairy Systems Inc., Gainesville, GA. “In the last couple of years, aseptic bottling systems have come into their own,” he says. “Finally, the market is gaining traction.”
He credits Nestlé’s success with kick-starting a bottle-filling growth spurt. Infant formula and geriatric drinks are migrating from retort to aseptic bottles, and more products will convert from retort and hot-fill as fill speeds increase. “We have a 400-bottles-per-minute in-line machine now, and we’ll be offering a higher-speed system in the near future,” Schweitzer says.
Stork is not subject to the legal wrangling surrounding aseptic filling. In fact, the company has lines in Steuben Foods’ Elma, NY facility, he adds, making litigation involving Stork fillers extremely remote. Consequently, some manufacturers are gravitating to Stork’s system for HDPE bottles. Milwaukee copacker Gehl’s now has four Stork aseptic fillers, according to Schweitzer.
A breakthrough commercial success would certainly assuage manufacturers’ trepidations. Even without a retail hit, aseptic processing and packaging is growing as a supply chain cost cutter. Those economies, coupled with technical developments that increase efficiencies in energy use and throughput speed, should help aseptic carve out a larger niche in food manufacturing.