Aaron L. Brody

More than 100 food and packaging professionals assembled near Washington, D.C., in September to attempt to critically analyze and sort out the blizzard of information that has been pelting all of us for the past several years. The three-day International Workshop on “Active” and “Intelligent” Packaging for Fruits and Vegetables, was co-organized by Binational (United States and Israel) Agricultural Research and Development (BARD).

Without trying to list all the technologies described by veterans such as Australia’s Michael Rooney, Canada’s Jung Han, and me—which filled an entire proceedings volume—I have selected a few that seem to fit the classification of new and intriguing. The keynoters were charged by the sponsors with coalescing the vast array of research, development, and near-commercializations.

Intelligent Packaging
As regular readers of this column recollect, active packaging senses and changes a package’s property, and intelligent packaging senses one or more measurable variables and signals the measurement through the package medium. One key concept integral to intelligence is that if you can measure a variable, sooner or later you should be able to control it.

• Maximum Temperature Indicators. Among the simpler intelligent measures are maximum temperature indicators—those that signal that, for example, the temperature of the ice cream package has risen to above the thawing point. If the temperature of the package is correlated with the temperature of the sensitive ice cream contents, then the maximum temperature indicator can be a useful tool

• Time–Temperature Integrators. Moving up the chain of intelligence, time–temperature integrators (TTIs) have been offered—and used to a limited extent—for more than 30 years. Such devices, relying on temperature-dependent enzymatic or melt flow characteristics of chemicals, should accurately reflect the temperature history of the contents. In turn, the temperature integral should correlate to the shelf life of the product contents.

Despite the fervent pronouncements of the purveyors of TTIs, the relationships of the readings to actual product experience do not necessarily correlate. Considerably more research on the relationship to product quality is required before truly meaningful TTIs can be incorporated into our packaging. Obviously, economics are also crucial to universal application. Not much imagination is required to leap from indicating signal to control—through self-cooling coupled with thermal insulation.

• Gas Sensors. Indicators of oxygen, water vapor, carbon dioxide and other internal biochemical and respiratory gases have been offered for many years as means to aid in modified-atmosphere packaging (MAP). Relative precision in internal gas concentrations should optimize the preservation effects. To date the major offerings have been oxygen concentration signalers, a good first step. Because MAP depends first on the temperature, integration of TTIs with gas concentration signals should be the objective of research. Since package polymers which can change their gas permeabilities with temperature, the idea of extending MAP (in which the gas concentration changes with time, depending on temperature, product, and package transmission) returns us to the originally intended controlled-atmosphere packaging. By knowing all the relevant variables affecting the product shelf life, overt controls may be engineered into the package structure and extended quality retention/safety can be the result.

• Radiofrequency Identification(RFID). Is there a nonpolitical subject that has received more media coverage since 2002 than RFID—driven not necessarily by the technology or the potential benefits, but rather by external decisions? Wal-Mart is reported to have directed its 100 leading suppliers to implement an RFID program for distribution packaging. The U.S. Dept. of Defense is also directing a program to facilitate control over distribution of its widespread supplies.

Bruce Welt of the University of Florida and Bill Roberts of Cryovac explained challenges of RFID for food and other packagers. The essential benefit of RFID is the ability to read/sense remotely from the package and its associated RFID tag. Information being communicated now mostly deals with identity, location and other inventory control data. In the future, when sensors for other variables such as temperature, quality measures, etc., are developed, a much richer information mine will be available to readers.

Most RFID devices today are passive—operating in the United States at 915 mHz. Passive RFID devices have no internal power/transmitter, and so respond to a signal from the reader, which delivers the power to transmit, based on backscatter modulation, the information in their memories. Currently, readers are transmitting and receiving at portals near which are the RFID devices on the packages (think theft deterrent devices on high-value hard goods).

Among the interesting challenges faced by those implementing the technologies are that microwave energy impinging on the package may be absorbed by aqueous package contents and so disrupt the accuracy of the return signal. Other microwave equipment can, of course, interfere. Metals in the package can reflect the energy. Read time is not yet instantaneous, requiring seconds—which, in this context, is not acceptable. Durability of the tags, now costing at least $0.50 apiece, through the rugged distribution system is still a question.

Active RFID devices contain internal battery power and memory and so are more expensive than passive devices.

• Smart Active Labels. Smart active labels (SALs) are battery-powered sensors that incorporate their information into a single, more complex chip design. An example is the Power Paper battery from Israel in the temperature-intelligent Temsens from Germany’s KSW- Morotek. The leading types are semi-passive labels for greater read–write range and temperature monitoring for data logging. At this time, the SAL information cannot be linked to or read by RFID readers. At well over $1 per unit, the idea of a SAL on every package or even every distribution case is a few fortnights in the future, but that is what they said about picture telephones during the 1939 World’s Fair.

• Bar Codes and Beyond. All of this intelligence communication represents a powerful tool to reach beyond the current Universal Product Code (UPC) bar codes printed on-packages that identify product and price. The next generation for primary package information sources would be two-dimensional codes printed on surfaces and containing many orders of magnitude more machine-readable data than the now-traditional linear bar code. Product description, ingredients, nutritional value, source, cooking or heating instructions, etc., may all be recorded for scanning by a PDF type of reader and potential visible display in a variety of venues. And obviously, the next generation beyond the relatively limited two-dimensional code would be SALs and/or RFID.

What’s Ahead
Some of the prospects for even more intelligent packaging might be depicted here:
• Inventory. In foodservice operations—as well as in homes—intelligent packaging can alert the operator/consumer on the inventory status of products: It can tell you that you are out of cereal and should order/go to the stockroom/pantry or go to the grocery/warehouse, and purchase/acquire more to replenish the consumer’s out-of-stock situation. The signal might be generated by scanning empty packages as they are discarded past a reader. Information can come from the package’s two-dimensional label, a SAL or RFID.

• Shopping. As consumers enter the retail grocery, they can be identified by their loyalty card (or RFID/SAL or other identification). Based on experience and past buying behavior, the consumer is directed/guided to the shelf sections containing the items of interest or on special or which have been specifically selected for him/her. Or to the sections containing the products that need replenishment based on home inventory control information signals. Big Brother is not just watching you: he is directing you.

• Pricing. On the retail shelf, RFID or SAL can receive a message from chain headquarters that the price of the item has declined and thereby change the price displayed on the shelf; the checkout laser scanner will receive the same information.

• No Checkout. Now that the bold and daring among us are bravely doing our own UPC scanning at retail grocery checkouts, we can envision the next development derived from SAL or RFID technology: no checkout. As the consumer walks out of the store, the RFID/SAL reader receives input identifying the contents of the shopping cart of the future and debiting the consumer’s bank account. No checkout, no clerk—just walk directly from aisle to the car and unload the groceries into the trunk (we must do something about this onerous heavy lifting task).

• Label Information. Intelligent packaging can issue information on the nutritional/nutraceutical attributes of the product specific to the individual consumer and the shelf life characteristics of the product and its experience. Instead of trying to read and interpret the nutrition label, the microcomputer provides an updated version in consumer-friendly format, in sound bites for those who are visually challenged.

And someday when all the stimuli and sensors have been correlated and standardized, information on the microbiological or biochemical quality will be visible or audible on the package. But that is a topic for another column.

• In the Refrigerator. Imagine, if you will, the consumer approaching the refrigerator and experiencing an audiovisual display quantifying the contents, effective age, nutritional value, quality, and spoilage or safety status of each item inside, or the incipient level to alert the person to use up the product before it would otherwise have to be discarded—all from the sensors on packages integrated with the bar codes, SALs, or RFID on the primary packages within the food storage compartment.

• Health Care. As the consumer removes the food from the refrigerator/pantry, the information is stored and compiled. Making the assumption that food not returned to the storage compartment is consumed, the information can be communicated to the medical team responsible for the consumer’s health. The nutritional intake—at least in the home environment—may thus be monitored. Before or during the patient-nurse-doctor interactions, frank discussions on compliance with doctor’s orders or suggestions may be held, with real data to support either side.

This ability to determine at least the general trends of diet is an outgrowth of the issue of patient compliance—consumption of drugs as required for prophylactic or curative reasons. Too many patients are impatient, or forget, or do not care enough, or for other reasons do not take the medicines prescribed by their physicians. To stimulate compliance—or remind the person that it is “time for your medicine,” numerous devices have been built into packages, the birth control wheel being one classical, but passive, example. Several devices have been developed to function more actively: to signal the patient audiovisually, to alert the caregiver, or to admonish the consumer if the package has not been breached or the pill not removed on time. The package cannot force the actual consumption, but it can bring the patient to the brink of actual pill-taking or food consumption.

• Microwave Heating. Microwave ovens are not created equally and do not grow old alike. The radiation pattern and hence the energy distribution within each oven is almost as distinct as a fingerprint. Furthermore, as experience has demonstrated, each food has its own singular microwave absorption characteristics, depending, among other variables, upon its mass, dimensions, components, loss factors, dielectric properties, heat capacities, temperature, phase, etc.

And position in the oven is yet another critical variable that draws that fine line between, for example, unpopped popcorn kernels, perfect popcorn, and the dreaded odor of burnt popcorn. And now, with microwave ovens being supplemented by forced air convection, infrared radiation from halogen lamps, etc., the combinations and permutations have reached almost to the infinite. Without microwave engineers and their software, how might a food intended for microwave reheating be reheated without becoming overcooked or having cold spots? There is the option of heating closed packages using steam, but, however effective, steam heating is hardly for all foods.

The tomorrow option—which does not exclude the steam assist—uses on-package information about the food and its package that couples with information about the microwave and the position of the food in the oven. The oven reads the package information and controls the cycles of microwave and other energy sources to optimally rethermalize the food. It even incorporates susceptors and shielding to ensure the proper heat in the shortest time—and communicates to the consumer that the food is indeed ready for consumption, at least from a thermal perspective.

Such package–oven interactivity using printed bar or two-dimensional codes has already been tested developmentally and found to be generally good, certainly orders of magnitude better than those vague musical on-package instructions such as “listen to the number of pops per second,” or the equally unscientific, put your finger in/on the food and determine if it has been heated enough (or too much, ouch!).

Smart packages wed to smart ovens is a marriage that cannot be set asunder and promises to greatly facilitate convenience and improve quality of the product the consumer experiences. And isn’t the objective of all food and food packaging science and technology the delivery of safe quality food?

Becoming Matter-of-Fact
The exploding world of active and intelligent packaging includes liberal doses of temperature (and time) measurement suggesting that someday soon, food packagers will incorporate this software into their structures—as routinely used as closures and easy-open features.

Because consumption temperature is such an important criterion of quality, the ability to sense temperature and feed the information back to heating equipment can be integrated into packages. Thus, another consumer problem can be overcome.

In the current clouds of information about information technology being married to packaging we are faced with a potpourri of possibilities—which fascinate even as they entice us. Most are quite functional in context, but require more development before they can be applied commercially. Active and intelligent packaging are disciplines that truly are possible but not until we are certain of the meaning of the information being generated. Apparently, like the realm of computers and the Internet, we are immersed in it, awed by, and hopeful for it, but hesitant because we do not seem to now how to use it to apply to packaging. To think about these technologies as means for location, inventory control, consumer identification and targeting, kitchen control or even food intake control leads us to the brink of ethical issues.

Our vision is that sooner than later we—all of us—will blend intelligent and active into our present conventional passive packaging and consumers will see it all as matter-of-fact and reflect occasionally, “What took them so long?”

Contributing Editor
President and CEO,
Packaging/Brody, Inc., Duluth, Ga.
[email protected]

In This Article

  1. Food Processing & Packaging