Will Aseptic Heat Up?
Gerber Products Co. spent several years and tens of millions of dollars to design, build and validate aseptic processing and packaging systems at its Fremont, Mich., baby-food plant. Meanwhile, an executive with Tetra Pak claims the firm validated more than 40 new aseptic products at its Denton, Texas, pilot plant last year. And a major food processor is validating a line of high quality, high margin foods with particulate for foodservice distribution in aseptic totes. Add to that the first U.S. aseptic filler installation from Krones Inc. and new techniques to facilitate validation of aseptic processes, and the technology may be reaching its dynamic peak.
Food scientists and engineers tried to kick-start aseptic in 1997 with the publication of Tetra Pak's FDA-approved aseptic process for potato soup. The process, developed in conjunction with the National Center for Food Safety and Technology (NCFST), was a template for designing a process system, determining residence time and temperature for low acid foods with particulate. Contrary to the excitement it generated in technical circles, the process generated a collective yawn in the commercial world. The procedures appeared too costly and complicated, and the payback from the investment was too uncertain. But those obstacles are being overcome, and 2004 could mark a watershed in the maturation of aseptic processing.
Two aseptic systems are involved. The first is known as Four Seasons, where freshly harvested fruits and vegetables are pureed, processed and packed in 3,000 lb. totes. The totes retain product integrity for up to 12 months, giving the facility the ability to formulate fresh-tasting foods year around. A new triple tube corrugated heat exchanger system was developed to retain as much texture, color and taste in the sterile foods as possible.
The second aseptic system works in conjunction with a kitchen where products are formulated. Equipment includes a multiverter agitation vessel with direct steam injection and surge tanks with variable speed agitators.
Aseptically packaging up to 285 million plastic cups a year represented a major change at the plant. A Hassia TAS low-acid f/f/s system sterilizes injection-molded cups with 150
Pushing the particulate envelopeAs impressive as Gerber's achievement is, it will pale if and when aseptic products with particulate enter the market. Whispers and rumors swirl around those projects but the expectation is that gourmet soups and medleys of meat and vegetables in sauce for restaurants will be ready for market this year. Depending on their market acceptance, those products either will usher in a new age of asepsis or set the technology back a decade.
Some of the development work is being done at NCFST. A point man in the 1997 potato soup project was Charles Sizer, then head of Tetra Pak's pilot plant and more recently NCFST director. Sizer recently resigned his office to return to academia and devote more time to commercial research projects. Based on his work at NCFST's labs in Summit-Argo, Ill., he is optimistic that foodservice soups and sauces "as good or better than a chef can make" will strike commercial pay dirt soon.
"As we improve our ability to visualize what is going on in the heat exchangers during the process, the validation process becomes less complicated and we learn how to make it more simple," says Sizer. "There are a lot of ways to skin this." Validation time has been reduced to six to nine months, equivalent to retort process validation and at a comparable cost.
NCFST's aseptic system uses magnetic resonance to measure residence time and core temperatures for the fastest moving and largest particulates by placing small magnets in their core and reading the signals at various points in the system. Signal data then is extrapolated to determine temperature. Unfortunately, the electronic noise in a commercial plant interferes with the signals and makes validation difficult. A possible solution is to insert micro thermometers into the particles, then use X-rays to capture temperature readings.
Sizer is working with Len Reiffel, inventor and chairman of Chicago-based Exelar, to find a food project for micro thermometry. Reiffel developed the technology with medical science in mind. Thermometers of 100 to 200 microns in size would be placed within the human body near a cancerous tumor before radiation treatment. By providing technicians with highly accurate, real-time temperature readings for the surrounding tissue, damage to healthy organs would be minimized.
"At this point, the system is just benchtop bits and pieces," says Reiffel. "We're looking for interested sponsors before we build a commercial system for food."
Sizer also is working with Alfa Laval, which has a heat exchanger at the NCFST, and FMC FoodTech, which developed Asepti CAL, a model used to calculate residence time for asepsis. Scientists and engineers at both FMC and Alfa Laval indicate their systems were part of an FDA-accepted validation project in August.
Getting up to speedLow-acid dairy foods are further along the aseptic development trail than other foods, and the segment has enjoyed notable technological and commercial successes recently. In January 2003, FDA granted final acceptance to Stork Food & Dairy's in-line aseptic filling system at Dean Foods' Morningstar Dairy in Mt. Crawford, Va. Three months earlier, FDA had given the green light to Tetra Pak's LFA-20 filler for high-density polyethylene (HDPE) bottles. Unlike fillers for paperboard composite packages, the HDPE fillers uses hydrogen peroxide gas to achieve package sterilization.
The LFA-20 filler is running at Jasper Products, a Joplin, Mo., aseptic copacker that first applied the unit to Dr Pepper/Seven Up's Raging Cow milk drink. In March, the line will also begin filling Bravo Foods' Looney Tunes Slammers, a line of flavored milk drinks.
"You're seeing more sophisticated dairy processors coming into the ESL and aseptic market, and that's driven by technological advances and the emergence of milk as a beverage, not just a food," according to Roy Warren of North Palm Beach-based Bravo. "We think aseptic's time has come."
Slammers will go a long way toward filling the LFA-20's production schedule, and that's part of the problem with aseptic, according to Patrick Carroll, technical director for Krones Inc., Franklin, Wis. Linear fillers only handle about 300 units per minute, "and people want to fill 600 to 1,000 per minute to pay for these very expensive lines," Carroll points out. Krones recently sold its first high-speed aseptic filling line to a Phoenix dairy, though the processor will market its output as refrigerated ESL.
Closely associated with high-speed brewery filling in the U.S., Krones has penetrated the European and Asian markets with its cold aseptic filling (CAF) technology. About 20 installations are running, including a unit that fills PET bottles with acidic juices and noncritical carbonated beverages. It came on-line last July at Pomdor, a Swiss beverage processor that replaced an existing filler because of food-safety issues. A key feature of CAF is its "isolator technology": an airtight, sterile compartment where package washing and filling is performed in a confined space. While Pomdor only fills about 400 bottles a minute, the modularity of the system allows expansion to 1,000, Carroll says.
The entry of new suppliers in the aseptic arena is putting pressure on established firms to innovate. Tetra Pak is responding with advancements such as see-through aseptic containers and a microwavable Brik. Film coated with silicon dioxide will replace aluminum foil to create a microwavable carton, according to Tetra Pak's Jeff Keller. The system is being used for sauces and dressings at Puljonki Ltd. in Puljonki, Finland. U.S. introduction of the package will occur later this year.
"Retail channel fragmentation is putting a lot of pressure on the chill chain to support products," points out Keller. "Club stores are really not refrigerated, and that is creating more demand for shelf stable products."
Some major processors are trying to fill the demand with aseptic products produced in overseas plants, an approach frowned upon by FDA. A better solution is to validate U.S. aseptic systems, and methods that "don't require two PhDs to babysit the testing process" will soon be available, one research scientist predicts. The combination of market demand and accessible technology should provide the critical mass needed to help aseptic finally realize its potential.
For more information:
James Van Wyk, Alfa Laval,
Len Reiffel, Exelar,
Jeff Dahl, FMC FoodTech,
Connie Brenneman, Krones Inc.,
Jeff Keller, Tetra Pak Inc.,
Greg Cherok, Lockwood Greene,
Charles Ravalli, Hassia,
732-536-8770, cravalli@ hassiausa.com