As if to prove my point that packaging is indispensable to food science and technology, more than 120 papers and posters directly related to food packaging are scheduled for presentation at the Institute of Food Technologists’ Annual Meeting, June 15–19, 2002, in Anaheim, Calif.
Depending on how we apply statistics, food packaging represents 7.5 % of all the technical papers offered. Perhaps more amazing is that 23 different universities are represented. Two departments/schools of packaging, Michigan State University and Clemson University, have submitted 14 presentations. Setting this—and every year’s—IFT program apart from the dozens of packaging trade shows and private conferences is the fact that only 13 presentations are from industry.
IFT’s Food Packaging Division is sponsor or co-sponsor of sessions involving nearly 60 of the packaging papers. The division has grown to be the organizer and sponsor most of the world’s technical presentations on food packaging—a distinct honor for IFT, which can now claim the title as the leader in packaging technology.
As might be expected from their origins, most of the papers are outside of what industry perceives as the mainstream. Some are ahead of commercial practice, some try to explain the science behind industry packaging, and some parallel what is in the field, but many lag.
The following are descriptions of selected papers and exhibits.
Here are presentations that should spark interest among professionals in the food technology and packaging technology communities.
Antimicrobials in edible films. By incorporating antimicrobials, edible films and coatings can protect food products from microbial spoilage and extend shelf life. With the many different edible films and types of antimicrobials available, edible antimicrobial films can be engineered for almost any food product. Several factors influence the type of film and coating material, such as intrinsic food properties (pH, water activity, and composition) and extrinsic variables (temperature and relative humidity in processing and distribution). Film and coating materials currently under study include lipids, resins, carbohydrates, and proteins.
In choosing an antimicrobial, says John Krochta of University of California– Davis, the effectiveness against the target microorganism is a primary consideration. Current antimicrobials include organic acids, bacteriocins, sucrose esters, and other natural antimicrobials (natamycin, lysozyme). Requirements for a practical and effective antimicrobial film or coating include antimicrobial effectiveness, controlled migration of the antimicrobial, good adhesion and interaction with the food product, and reasonable application procedure. Paper 24-1, Sunday afternoon
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Natural or formulated antimicrobials. Chemical agents exhibiting antimicrobial activity may be either synthetic or naturally occurring biological substances. These substances may exhibit antimicrobial properties in foods or may be used as hurdles in multifactor food preservation systems. According to USDA’s V.K. Juneja, factors to be taken into account for use in food products include physical and chemical properties such as chemical reactivity, solubility, dissociation constant, toxicity; composition and properties of the food; and the types and numbers of microorganisms to be controlled. An ideal antimicrobial should not contribute to the development of resistant strains. Antimicrobial mode of action falls into one of three categories: reaction with the cell membrane, causing increased permeability and loss of cellular constituents; inactivation of essential enzymes; or destruction or functional inactivation of genetic material. No antimicrobial is able to preserve a grossly contaminated product. Paper 24-2, Sunday afternoon
Antimicrobials and package system design. Antimicrobial packaging systems can extend the lag period and reduce the growth rate of microorganisms to prolong shelf life, states University of Manitoba’s Jung Han. In addition to the containment and protection functions of food packaging, the antimicrobial packaging system must be designed with considerations of inhibition mechanism of the incorporated antimicrobial agents; chemical nature of the antimicrobial agents; physical chemistry of foods; microflora of foods and physiology of target microorganism; migration kinetics of antimicrobial agents into foods; distribution environments; package manufacturing processes; toxicity and regulatory issues; sensory properties of the antimicrobial agents; and machinability and processability of the antimicrobial package materials. Paper 24-3, Sunday afternoon
Regulatory perspective on antimicrobials in packaging. Antimicrobial packaging is treated as an additive by regulatory agencies. Consequently, it must pass the same strict reviews as other additives before being permitted for use in foods. In the past, regulatory approval of such new additives systems could take extended periods. However, the Food and Drug Administration’s Bob Brackett asserts that his agency now allows for expedited reviews of new compounds that show promise in enhancing food safety. Paper 24-5, Sunday afternoon
Ozone in aseptic processing and packaging. In aseptic packaging, composite paperboard or plastic packages for fruit drinks are often sterilized by hydrogen peroxide, which may leave residuals, says A.E. Yousef of Ohio State University. Ozone is a viable alternative because it is a potent disinfectant, with broad inhibitory spectrum and strong sporicidal action. Additionally, ozone decomposes rapidly, leaving no residues on the package. Natural contaminants and dry bacterial films on these surfaces are relatively easy to inactivate by ozone. Paper 49-1, Monday afternoon
On-line electron-beam sterilization of polymeric containers. The objective of research by J. Dunn of the National Center for Food Safety and Technology (NCFST) was to evaluate the effects and capabilities of employing a relatively low-energy electron beam to treat the interior of an open-mouthed container for aseptic or extended-shelf-life packaging. This treatment used multiple scattered electrons to wash the entire internal volume of the bottle, including non–line-of-sight regions, with a controlled radiation dose. Results show that high levels of sterility assurance can be obtained without changes in appearance or increases in extraction properties of the package material. The method requires lower electron energy, machine size, and power than otherwise required for penetration through the container (“through-the-sidewall” treatment), and includes the benefits of high throughput rate capability, real-time on-line electronic dosimetry, and ease of shielding and integration into existing lines. Paper 49-2, Monday afternoon
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Bag-in-box packaging. Bag-in-box has grown into a global packaging format for a variety of liquid food applications, including tomato paste, fruit purees, liquid eggs, soft drink post-mix syrups, smoothie mixes, juices, fluid milk, ice cream mixes, wine, condiments, sauces, and edible oils. It is gaining as a replacement for cans, pails, jars, and bottles. Innovations in dispensing, says Scholle Corp.’s D. Proper, are driving growth in the bag-in-box market, especially at the end-user foodservice operator level. Critical to dispensing is the bag fitment and dispensing connector system. Historically, bags ranged in size from 1 L to 330 gal and were configured “pillow” style. Bags can now reach as large as 24,000 L. They can be designed as form-fit or shaped bags and are most often used to line intermediate-bulk or bulk shipping containers. This innovation in design allows for ease of filling (especially high-viscosity products) and better product evacuation and shipping performance. Paper 49-6, Monday afternoon
Enhancing food security through packaging. Almost all commercially available tamper-evident packaging currently relies on the physical destruction of a tamper-evident feature. To minimize inconvenience, the design of such features must take into account the physical strength of consumers, especially the elderly or disabled. There appears to be no commercial tamper-evident system that uses an indicator to identify the point of entry of a needle into flexible packaging, even though this form of tampering appears important.
The objective of work by M. Kelly and coworkers of Food Science Australia was to develop a tamper-evident system for flexible packaging based on chemical reactions initiated at the site on the package at which tampering has occurred. A change in color of a colored indicator incorporated into package structures is activated when the package is breached either accidentally or deliberately and the indicator layer is exposed to the environment.
The system has been used to detect package damage at the welds, or when a hypodermic needle has punctured the pack. The point of damage becomes the center of an expanding area of changed color, magnifying the point of color change sufficiently to be readily detected by eye. Paper 72-1, Tuesday morning
Nondestructive leak detection in polymeric trays. Pressure-differential nondestructive leak testing systems can potentially offer inspection regimes that exceed current GMP guidelines for visual inspection. These devices should be able to reliably identify all defective packages they are intended to test, should not damage defect-free packages in the process, should be easy to operate and maintain, and should operate at speeds that do not compromise line efficiency.
A benchtop nondestructive pressure differential leak tester was evaluated by M. Pascall of NCFST. Force/decay responses to leaks, changes in the package headspace volume, and differences in the seal strength of sample trays were measured. Leak detection evaluation was done using artificially created channel leaks in the sealing areas and pinholes in the lids. Paper 72-2, Tuesday morning
Ultrasonic determination of tray seal strength. The effectiveness of ultrasonic imaging for nondestructive assessment of seal strength in polymeric trays was performed by M. Pascall and coworkers at NCFST. Ultrasonic measurements were conducted at 20 MHz, using an immersion technique in a pulse/echo mode. The captured signal amplitudes of the reflections from the samples were digitized and analyzed to construct high-resolution C-scan ultrasonic images of the seals. Paper 72-3, Tuesday morning
Electronic nose analysis of printing solvents. The objective of work by P. Mallikarjunan and coworkers at Virginia Polytechnic Institute & State University was to compare the performance of electronic nose systems as a complementary analytical tool for quality control of retained printing solvents in packaging. Three electronic nose systems using different sensor technologies—metal-oxide semiconducting sensors, conducting polymer sensors, and quartz microbalance sensors—were used to detect food packaging taints. This study used ten film products containing varying levels of retained solvents. The results indicate that electronic nose instrumentation can be used as a complementary discriminatory tool in quality control for packaging. Paper 72-5, Tuesday morning
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Oxygen sensors for noninvasive measurements. New opto-chemical sensors developed by A. Bizzarri and coworkers at Australia’s Joanneum Research allow nondestructive measurement of oxide inside transparent packages or containers. The sensors are based on the principle of luminescence quenching and consist of an O2-sensitive element included in the package and an opto-electronic readout instrument to measure from a distance, in the presence of ambient light, and with known luminescence backgrounds (e.g., from the package material). The element consists of an O2-sensitive dye dissolved in a polymer material.
The instrument measures luminescence lifetime via a phase measurement technique. Depending on the element and the optical components, it is possible to perform sensitive measurements in different ranges of O2 partial pressure. These sensors are claimed to be suitable for applications in packaging technology and food research, on-line quality control of vacuum and modified-atmosphere packaging, and leak inspection. Paper 72-8, Tuesday morning
Lighting effects on packaged foods. Food products packaged in transparent and translucent films can deteriorate during retail light display as a result of changes in sensitive pigments or lipids. Oxidation of these constituents leads to fading or discoloration and off-flavor development, assert Jim Acton of Clemson University and Leslie Cook. Lighting environments provide energy for oxidation.
In most photo-oxidation reactions, results show that varying the light intensity has an Arrhenius-type effect on the reaction rate and is also oxygen dependent. Only under conditions of temperature control and nearly complete elimination of oxygen, such as through application of in-package scavengers or the use of appropriate oxygen-barrier films, does product shelf life extension occur. Current retail display lighting for foods and lamp selection are neither standardized between stores nor within stores.
Spectral irradiance of lamps relating to ultraviolet (UV) energy output provides an indication of potential energy available to detrimentally affect food products. Plastic lens diffusers or coated cover glass on lamps effectively reduce UV output. Similarly, for “worst case” products that are extremely sensitive to the UV portion of the lighting spectrum, UV-absorbing substances may be incorporated into the package film. Paper 81-3, Tuesday afternoon
Incorporation of functional ingredients in packaging. As the inexorable shift of package materials and structures from passive to active forms occurs, food package converters and users are confronted with a formidable myriad of challenges. In the past, the concerns had to do with blending, alloying, and bonding of compatible compounds or physical mixing of incompatible materials. Tomorrow, these combining actions must be overlaid with overt interaction of package component with package content.
Oxygen scavengers must be actuated when needed; and the oxygen from the interior must reach the scavenger and react or interact; and the reaction must not release its end products. Moisture scavengers must be activated to remove moisture without damaging the product. Odor removers should ideally act on adverse volatiles while leaving the desirable aromas. Systems to add desirable colors and flavors should deliver them in a controlled manner.
The package converting mechanisms, such as coating, lamination, mixing, coextrusion, coinjection, etc., for incorporating active components into package structures to economically maximize the beneficial effects are discussed by A.L. Brody of Packaging/Brody, Inc. Paper 81-4, Tuesday afternoon
Predictive shelf life testing. Maintenance of food quality and safety is dependent on the understanding of these reactions, the influence of the environment, and the successful limitation of the reactions most responsible for spoilage or loss of desirable characteristics. The shelf life of a food is based on the proportion of consumers a company is willing to displease at a given time and for the given distribution conditions. It is the period during which the product will retain an acceptable level of eating quality for that given percentage of consumers from a sensory point of view, while still maintaining safety. It depends on four main factors: formulation, processing, packaging and storage conditions.
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To answer the critical questions, “What is the shelf life of the food?” and “Will it reach the consumer in acceptable quality?” food scientists, such as T.P. Labuza of the University of Minnesota, responsible for product development resort to educated guesses based on the particular processing scheme and estimated distribution conditions, as well as experience, or run limited experiments under abuse conditions and try to extrapolate the obtained limited data to the projected shelf life. This presentation reviews the basic kinetic approach that can be used for shelf life prediction. Paper 81-5, Tuesday afternoon
Magnetic resonance detection of bacterial contamination. An automated magnetic resonance (MR) system that can nondestructively test packages of shelf-stable low-acid foods for spoilage and contamination was evaluated by M. Pascall. MR relaxation times were correlated with the growth of Bacillus stearothermophilus and Bacillus subtilis in commercial soymilk packaged in plastic. MR was also studied to determine if it could differentiate between regularly processed cheese sauce and “spoiled” cheese sauce. The results showed that MR has the potential to be used for nondestructive identification of contaminated or underprocessed foods in polymeric packages. Paper 87-3, Tuesday afternoon
Sous-vide processing of spinach soup. A study by G.T. Kim and coworkers at two Korean universities applied sous-vide processing to spinach soup seasoned with fermented soybean paste, a typical Korean soup. The feasibility of sous-vide technology was examined for sensory, microbiological, physical and chemical qualities. Sous vide involves hot filling, pasteurization based on inactivation of psychrotrophic Clostridium botulinum, and rapid chilling. The processed products were stored under refrigeration. The seasoned spinach soup processed by the sous vide method exhibited a sensory quality comparable to that of fresh soup. The product was stable in microbial quality during storage for 35 days at 3°C, but only up to 10 days at 10°C. The seasoned spinach soup may be processed by the sous vide method and stored for appropriate time periods under chilled conditions. Paper 15-F3, Sunday morning
Antibacterial treatment of fresh-cut packaged lettuce. Microbiological analyses by Kay McWatters and coworkers at the University of Georgia showed that 2% hydrogen peroxide at 50°C effectively reduced pathogenic organisms on fresh-cut iceberg lettuce, but effects on sensory characteristics were unknown. Objectives were to determine effects of this antibacterial treatment on consumer acceptability of fresh-cut lettuce. The antibacterial treatment was effective in maintaining sensory quality during 15 days of storage, compared to untreated controls, provided that the lettuce had considerable green color initially. Findings from both the microbiological and sensory studies indicate positive potential for the hydrogen peroxide/mild heat antibacterial treatment. Paper 76-C5, Tuesday morning
Sensory evaluation of MAP ground beef. Color is a primary factor affecting consumer selection of fresh beef. Bright red color associated with freshness can be obtained by packaging beef in an 80% oxygen atmosphere. Such modified-atmosphere- packaged (MAP) products are case ready. Oxygen, however, promotes oxidation of lipids in the beef, which can affect the flavor of the ground beef.
The objective of this study by P. Jayasingh and coworkers at Utah State University was to evaluate palatability and color of ground beef stored in high-oxygen MAP (80% oxygen and 20% carbon dioxide), compared to controls stored in traditional reduced oxygen in oxygenimpermeable chubs. Patties from both treatments bloomed to red. Aerobic plate counts and TBA numbers increased. Flavor of samples in high-oxygen MAP were rated less desirable after 6 or 10 days storage. The researchers concluded that use of 80% oxygen MAP has a detrimental effect on the palatability of the ground meat. Paper 46G-17, Monday morning
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Barriers to botulinal growth in MAP bakery products. Extended shelf life of minimally processed bakery products stored at ambient temperature can be achieved through modified-atmosphere packaging. However, there are regulatory concerns about the safety of these products, which have the potential to support the growth of Clostridium botulinum. While no botulism outbreaks have been associated with bakery products, the severity of botulism justifies the need for incorporating additional barriers to prevent the growth of and toxin production by this pathogen, should it be present in the final baked product. Preliminary studies by D.P. Daifas and coworkers at McGill University showed that combinations of ethanol, pH, and aw could be used as effective barriers to alleviate the safety concerns of MAP bakery products. Paper 87-9, Tuesday afternoon
Carbon monoxide packaging and pork shelf life. The bright red color associated with fresh meat is an important feature to consumers, and retention of this attractive color is the most common determinant of retail shelf life for meat cuts. Modified-atmosphere packaging has been shown to increase the shelf life of fresh meat, but color is often less appealing. The use of carbon monoxide (CO) in MAP with high levels of CO2 has the potential to produce both stable bright-red color and increased shelf life of meat cuts. T.R. Krause of Iowa State University investigated the potential for low-level CO combined with elevated CO2 in package atmospheres to extend shelf life, improve color, and reduce purge of fresh pork and injected fresh pork. The results showed that CO significantly improved color stability and sensory characteristics of pork in modified-atmosphere packages during refrigerated storage. Paper 91E-27, Tuesday afternoon
The above series of abbreviated abstracts barely describes the breadth and depth of data and information on food packaging that is scheduled for presentation at virtually every moment of the IFT Annual Meeting. Packaging is integral and indispensable to food science and technology, as will be seen throughout the sessions.
Here are brief descriptions of selected exhibits related to packaging.
Universal container, the Unicon, represents the latest in Intermediate Bulk Container (IBC) technology. Features include electronic tracking, a hinged folding design, sight-glass front panel, and a total discharge sump. The container is available for leasing. Also available is the Plastic Foldable Container for nonliquid food products, which greatly reduces the opportunity for introduction of foreign materials. CHEP, 8517 S. Park Cl., Ste. 400, Orlando, FL 32819 (phone 800-243-7872, fax 407-355-6495), Booth 8338
IBC for bag-in-bin applications, Model MB3, is all metal and has a large 1,400-L (370-gal) capacity. It is suitable for packaging such products as frozen concentrated orange juice, anhydrous milkfat, and aseptic juice concentrates. A variety of high-quality bags with fitments for any application, both solid and liquid, are available. Goodpack USA, Inc., 550 N. Commons Dr., Suite 106, Aurora, IL 60504 (phone 630-898-0888, fax 630-898-1888), Booth 4107