COLD-FILLING IS A TECHNIQUE that food processors intend to use more of during the next 5 years. That was one of the findings of the 1992 FOOD PROCESSING and Food BUSINESS Packaging Survey.
Another finding indicates that hotfill, aseptic, and retort--all shelf-stable filling/processing techniques-- will combine to represent the highest new product R&D activity levels during the next 5 years. These are two contrasting trends that warrant further examination. In this article, we'll concentrate on cold-fill. In subsequent articles, we'll take a closer look at hot-fill, aseptic (a special breed of cold-fill), and retort approaches.
While some cold-filled products can be rendered shelf-stable by preor post-fill heat treatment and by their acid/pH levels, a number of cold-filled products are not storable without refrigeration. In fact, some of the best candidates for cold-filling are products marketed in a frozen state.
What is cold-filling?
Depending on the product application, the definition of cold-filling can vary greatly. Based on our conversations with several industry experts, we will, for the purposes of this article, define cold-fill temperatures as anything below the hot-fill range of 170195F and the pasteurization range of approximately 165 -2 5OF. Cold-fill can range from just above freezing on through ambient temperatures all the way up to the boundary of hot-fill. So, we're talking about 34F-I60F--a tremendous expanse.
Some processors opt to "cold"-fill (or ambient-fill) at slightly higher than room temperatures to prevent condensation on the packaging. Some choose to cold-fill at temperatures below 45F to optimize flavor freshness. For still other operations and products, a "cold"-fill of 150-160F may be the most appropriate option. Ketchup, for example, might be "cold"-filled at up to 16OF. Some juices, on the other hand, might benefit from a "cold"-fill at 120-140F.
Cold-filling traditionally has been the technology of choice for a broad range of products and is often used in combination with a pre- or post-pasteurization step. Milk and various other dairy items, carbonated soft drinks, sparkling waters and sparkling wines, beers, many juices, ketchups and a variety of other condiments, dressings, liquid eggs, deli-type salad products, and a gamut of frozen foods are cold-filled.
Cold-filling at Papetti's
With cold-filled product applications such as milk and liquid eggs, the product is pasteurized with a quick blast of heat, held for at least 31/2 minutes, then cooled for filling. Dr. Larry McBee, Technical Services Manager for Papetti's Hygrade Egg Products, Inc., points out that coldfill is really the only practical approach to packaging liquid egg products. Hot-filling or retorting methods would subject the eggs to extendedtime heat conditions that would "cook" the eggs out of their liquid form. Likewise, an aseptic flash-heating at 270-290 F for just a matter of seconds would be too much and would cause the liquid eggs to set up.
Dr. McBee outlined the processing/cold-filling procedures used at Papetti's. The company uses CherryBurrell (now Evergreen) cold-fillers for its gabletop carton-packed eggs, and Scholle cold-fillers for its pouchpacked eggs. Gabletop packaging is sanitized with hydrogen peroxide and heat, and pouch materials are supplied to Papetti's in sterilized form. The liquid eggs are introduced to filling operations after the product has been pasteurized, held, and cooled. Filling is done under clean-room, HEPA-filtered-air conditions. Noted McBee, the cold-fill procedure is, in essence, a clean fill, but the product is not aseptically processed.
All Papetti's products are coldfilled into gabletop cartons, bag-inboxes, cook-in-bags (on a Cryovac filler), or metal cans and are distributed and marketed in refrigerated or frozen form. None of the products contain preservatives. Papetti's extensive foodservice and retail consumer line includes such items as "Table Ready"--a 12-week refrigerated shelf life liquid whole egg product with citric acid (to stabilize color); "Healthy Morn"--a 100% cholesterol-free egg substitute containing 99% egg white /and fortified with vitamins and minerals; and "Lite-n-Hearty"--a special egg blend that contains 75% less cholesterol, 75% less fat, and 50% fewer calories than shell eggs. The Elizabeth, NJ-based company also can supply custom liquid egg blends for industrial ingredient applications.
Cold-filling at Cream Products
Cream Products, Inc., a Chicagobased dairy, cold-fills liquid toppings and other refrigerated dairy and nondairy items into gabletop cartons.
The processor uses Tetra Pak TR/7 cold-filling machines with sterile air supply for "ultra-clean" filling. The liquid toppings are ultra-pasteurized at 284F and filled at temperatures below 4OF. The finished products have extended refrigerated shelf life.
John Bluemke, Cream Products President, points out that the combination of an ultra-pasteurized product, Tetra Rex cartons, and the TR/7 cold-filler work together to provide extended shelf life. "We wanted a reliable system that would put us into a good competitive position against other products. We've been very pleased with the results we have achieved--they have allowed us to exceed the dating offered by a number of our competitors."
Cold-filling for beers, soft drinks, and juices
In the beer industry-a traditional user of cold-filling--the fill technique is teamed up with cold filtration and pasteurization to render shelf-stability to the packaged product in non-refrigerated storage. The heat treatment of the beer (to as much as 60C) to achieve pasteurization may be done pre- or, more typically, post-filling. In either case, the middle steps include (1) using filtration to remove microbial matter and yeast and protein sediment; 2) injecting carbon dioxide gas to create carbonation; 3) chill-proofing and a second filtration just before filling the beer into containers.
Carbonated soft drinks also are cold-filled. In fact, it is important to note that none of the categories of carbonated beverages--beer, soda pop, sparkling wines, sparkling waters-can be hot-filled. The tolerable fill range for carbonated beverages is about 34F-80F. Hot-filling would destroy carbonation.
Many juice processors use coldfilling, pasteurization, and filtration combinations--along with refrigerated distribution and storage. Coldfilled juices marketed in a refrigerated state typically are packaged in plastic bottles or gabletop cartons. Hot-filled glass-packed or PET-packed juices are shelf-stable.
As previously noted, aseptic processing and packaging is defined as one type of cold-fill procedure. Aseptic juice is "flash" pasteurized for a matter of seconds at high temperatures (270-290F), then quickly cooled down and filled into sterile containers in a sterile filling chamber.
In a non-aseptic coldfilled juice operation, the juice might be pasteurized, then cooled quickly down to about 34 F, then filled, sealed, and refrigerated.
The key differences between an aseptic cold-fill and a non-aseptic cold-fill procedure are that in a non-aseptic operation the product is heat-treated at a much lower temperature for a longer period of time, the containers are not necessarily pre-sterilized, and instead of a sterile filling chamber, clean room conditions are employed.
FBI Brands, a Canadian juice processor, uses a patented non-aseptic cold-fill procedure which consists of filling the juice at room temperature (60-80F) into 5-layer gabletop cartons, sealing, then pasteurizing. These juices are rendered shelf-stable. (See article in May '91 FP for details on this system.)
FBI Brands points out that the cold-fill system offers significant cost and speed efficiencies over hot-fill and aseptic systems, while providing comparable shelf life. The processor further notes that carton seals are not placed under as much stress. For example, when hot-filled/sealed gabletop cartons are subjected to the cooling process, the cooled juice contracts, creating a vacuum inside the carton.
Consequently, the top seals on the hot-filled cartons must be extremely strong in order to maintain full integrity. No vacuum is created by the cold-fill process. Initial headspace conditions remain the same from fill through post-seal heat treatment.
FBI's patented technology is called "POP-PAK" and is being licensed to other processors. GuidaSeibert Dairy Co., New Britain, CT, became the first U.S. licensee and launched its "Fast Trac" line of shelfstable, cold-filled gabletop-packed juices in January 1992.
Cold-filling at Campbell Soup
Cold-fill has believers at Campbell Soup Company. One spokesman, a packaging expert who requested anonymity, concurred heartily with our survey findings that cold-fill would grow over the next several years. "We do cold-fill whenever it makes sense. The faster you can fill perature, the better the quality of the finished product will be. Also, when you fill hot, the process costs more money. Campbell is doing serious research on cold-fill applications."
Even products that are eventually retorted can benefit from cold-filling, according to Campbell. In products such as soups or pastas, a cold-fill helps protect against the breakup of components. Meatballs are more likely to stay whole, and vegetable chunks less likely to turn to mush in a cold-fill system. "You get better product quality can-to-can with a colder fill," said our source.
Another Campbell representative commented on the application of cold-filling to frozen dinner and entree-type products. "Virtually all our frozen gravies and sauces are coldfilled. Typical filling temperatures for frozen dinner components are in the 32-45 F range."
Cold-fill pros & cons
Cold-fill is limited in terms of its ability to render shelf-stability. However, when combined with pre- or post-fill heat treatment, cold-fill can offer a relatively economical route to the shelf-stabilization of some foods.
Non-aseptic cold-fill equipment is lower-cost than aseptic systems. However, clean-room cold-filled product shelf-life often may be shorter, and for non-acidic products, refrigerated storage typically will be needed. Preservatives also are more likely to be incorporated into coldfilled products.
Non-aseptic cold-filling demands clean room conditions. Meticulous sanitation practices are critical to minimizing microbial load. HEPAfiltered air and possibly gamma-irradiated or otherwise sterilized packaging materials could factor into a coldfill operation.
Compared to hot-fill or retort, cold-fill can facilitate maintenance of fresher product flavors and decreased loss of nutrient values. When dealing with viscous cook-chill-fill products such as soups, stews, desserts, or components of prepared frozen meals, cold-filling temperatures may facilitate more accurate fill weights and more uniform distribution and stabler suspension of particulates. Furthermore, since the product is filled at a lower temperature, less time and fewer BTUs are required to chill the product after filling and sealing. This can translate to significant energy cost savings over time for products intended to be distributed and stored in a refrigerated or frozen state.
There's a diversity of opinion about packaging material cost advantages associated with cold-fill versus hot-fill. For instance, some experts point out that, since cold-filled pouches are subjected to less heat stress, cold-filled products (especially those that are stored and shipped in a refrigerated state), can be packaged in pouch films that are downgauged and incorporate less sophisticated structures. This can result in significant material cost savings. It also theoretically can render the film more supple and machineable and, consequently, facilitate faster machine speeds. However, other experts note that, since cold-filled products generally have a more fragile shelf life than their hotfilled counterparts, it may not be wise to sacrifice film gauge and barrier structure in cold-fill applications.
The outlook for cold-fill
The food and beverage processors who responded to the FOOD PROCESSING/FOOD BUSINESS Packaging Survey have sent the message that cold-fill will figure heavily into their plans over the next several years. With that message in mind, we'll be watching closely for signs of new activity in this area.
In gathering background and input for this article, we contacted several food companies, packaging machinery suppliers, and packaging consultants for their reactions to those findings. Their input was most valuable, appreciated, and diverse. The opinions were about as wide-ranging as the temperature parameters of coldfilling. To illustrate, here's a pointcounterpoint about cold-filling from two of food packaging's best-known gurus.
Cold-filling It's hot ! Dr. Mel Druin of M.L. Druin & Associates commented: "Cold-fill offers food processors increased quality, productivity, and lower packaging cost versus conventional hot-fill processes. With hot-fill, the product is transferred hot and often is recirculated before package filling. This extended heat history can lead to product degradation and/or loss of flavor essences. Cold-filling thus allows for more consistent and reliable product quality.
"Cold-filling also results in less or no vacuum formed within the package compared with hot-fill. This eliminates or minimizes the propensity for paneling of the package and allows significant flexibility in using thinnerwalled, lighterweight, less costly packaging materials than is required for a hot-fill process. Since paneling is much less an issue with cold-fill, headspace can be significantly increased during the filling operation. This results in a consumer benefit of being able to shake the product contents prior to opening. It also eliminates the seal contamination problems encountered by product splashing or foaming during hot-filling. The heat seal achieved with coldfill is, therefore, more consistent, reliable, and easier to open.
"Cold-fill can result in increased line efficiencies and productivity with less product and packaging waste. In addition, during the 90s and beyond, as more plastic packaging for refrigerated and shelf-stable foods is converted from contact clear polyolefins (PP, PE) to crystal clear PET, cold-filled products will be able to employ PET materials requiring minimum or no heat-setting. Hot-filled products require PET that is heat-set (conditioned) in the mold to be able to withstand the high filling temperatures. This heat-setting adds significantly to packaging costs.
"Aseptic is indeed a cold-fill technology. However, more conventional cold-filling is capable of handling both high- and low-acid foods and beverages with or without particulates. With current aseptic processes solid particulates are limited in size to assure safety considerations. While the effectiveness of any filling technique is product-dependent, in many cases current aseptically processed and packaged foods generally offer no significant quality or taste advantages over hot-filled or cold-filled products. Aseptic products also tend not to offer significantly longer shelf life than hot-filled or shelf-stable cold-filled products.
"For these reasons, I see cold-fill growing considerably in use during the 90s as an alternative both to hotfilling and aseptics. Cold-fill offers advantages in overall investment and packaging costs, product quality, and consumer appeal."
It's not ! Tom Szemplenski of the consulting firm Aseptic Resources, Inc. holds a much different view. "The market for foods that are cold-filled generally will not experience much growth over the next 5 years. Coldfilled foods are categorized two ways: foods that are cold-filled and distributed refrigerated, and those that are cold-filled, but shelf-stable due to controlled water activity or the addition of preservatives.
"Although the consumer associates refrigerated foods with freshness and higher nutritional value, there are a number of aspects that deter the growth of foods that are cold-filled and distributed refrigerated. Cost of refrigeration and the maintenance of a refrigerated state is a primary hinderance to market growth for these types of foods. Associated with this cost is the competition for the ever so limited shelf space in the grocery store. Limited shelf space and, in many cases, increased packaging cost will lead to the obstruction of a market many predict will grow rapidly.
Those who are optimistic might want to refer to the lack of success that marketing giants Kraft and General Foods (then separate) had with 'Chillery' and 'Culinova.' These innovative refrigerated products experienced a very short market life.
"Refrigerated puddings are one area that has experienced tremendous growth over the last several years, but except for specialty puddings such as reduced-calorie or nutrient-enriched varieties, this market is now saturated and will see little growth. There will be some innovative products that will be the exception to the overall market trend. Low-cholesterol eggs marketed refrigerated will be one exception. Products like these, however, will be few and far between.
"Cold-filled foods that can be distributed shelf-stable by controlled water activity or by use of preservatives will not see much market growth in the near future either. The use of controlled water activity often results in extremely viscous products that are not organoleptically appealing to the consuming public. Many times these foods require a reconstitution process by the consumer and, therefore, are not regarded as being a truly convenience food. Most marketing experts will agree that the trend toward food products with littie or no preservatives will continue. This will result in little if any market growth for shelf-stable foods containing preservatives."
Hearty thanks to Mel and Tom for being willing to publicly stick their necks out on this question. In time, we shall see on which side of the growth curve cold-fill falls. Place your bets!
Cold-fill--the underrated, underreported workhorse
A packaging survey recently conducted of readers of FOOD PROCESSING and our sister book FOOD BUSINESS provides some intriguing revelations about trends and directions in the 90s. For example, the survey found that, of all the filling technologies, cold-fill is the one that a majority of food/beverage processors intend to use more of during the next 5 years.
Well, frankly, that's not where I or most other packaging writers have been focusing our attention. All of us have been to some degree mesmerized by the natural allure, the sex appeal, of more "cutting edge" technologies--retortable plastic, hot-fillable PET, and aseptic--which is itself a special breed of cold-fill.
Cold-filling (for non-aseptically processed products) has been out there doing the job for a very long time, largely unnoticed and unheralded. It's been a veritable industry workhorse. Milk, beer, carbonated soft drinks, many juices, liquid eggs, ketchups, dressings, and countless refrigerated and frozen products are cold-filled. Ironically, the long-time effectiveness of cold-fill has rendered it a non-subject ! With the recent NBA Championship series still a fresh, sweet memory, I can't help but think about Horace Grant--the steady, reliable, assist and rebound "warrior" as his coach calls him. Most of us who followed the series got so easily and eagerly wrapped up in the flashy glamor of the "superstars," the high-point players--Michael, Clyde, and Scottie--that we didn't pay a great deal of attention to Horace. He was (I can't resist) taken for Grant-ed.
It's much the same with cold-fill technology. It plays a critical role in the food industry, but has been generally ho-hummed by the trade media, packaging conference coordinators, and by many food company staffers. After all, if it's not new, it's not news. Wrong[ There seems to be a revived recognition of the versatility and virtues of this technology. Cold-fill is becoming "trendy!"
Certainly, aseptics, hot-fill, and retort should continue to get their due. They all are indisputably important technologies having a definite impact on the industry. However, it is time to take a fresh look at cold-fill--as the respondents to our reader survey are doing. What are the temperature parameters,' the existing and potential applications, the pros, the cons, the economics, and the mechanics of cold-filling? All these questions are examined in this special report. Read it and react. We always enjoy heating from you.
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|Date:||Sep 1, 1992|
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