The principal objective of food packaging is protection from the adverse effects of a perpetually hostile environment throughout the distribution system. Protection is usually achieved by erecting a barrier between the exterior and the interior, where the food is ensconced. In basic food packaging parlance, almost all food is sensitive to the effects of oxygen, light, moisture, temperature, and critters ranging from mammals to microorganisms. Food scientists and technologists apply their efforts to “preserve” the food contents, that is, to minimize problems with the safety of interactions of food and consumers, whether human or animal.
Preservation is a series of systems scientifically engineered to protect the food products from the effects of dirt, microorganisms, and external and internal assaults, almost all of which are nature’s way of converting the food back to its origins in the expectation of renewal. Contrary to some ill-conceived common perceptions, food preservation is not some concoction of evil chemicals injected into the food to effect permanence on this planet. In reality, preservation is precarious, and almost all processes safe for consumers, such as heat and chill, water activity control, and packaging, are very temporary—altogether too short to achieve without tight controls.
The Safety and Quality of Fresh
There is as of yet no magic silver bullet that can preserve food forever and a day. And gathering crops from our backyards (of a New York City or Chicago apartment building, for example) and quickly toting them to our kitchens under ambient conditions for instant preparation cannot ensure either safety or quality. The fastest method of spoiling, or even optimizing conditions for growth of pathogenic microorganisms, is farm-to-table without any intermediate processing or packaging.
If you doubt my assertion, I suggest observing the farmers market in your neighborhood at the middle or end of the day and not at dawn when the dew is still on the leaves. The food spoilage is appalling: How much can be held over another day for the next dawn’s customers? An even more dramatic question is this one: Why is starvation and hunger so prevalent in geographies that foster fresh, unpackaged food? And why do the populations of these countries suffer from nutritional deficiency diseases and foodborne illnesses at a rate many multiples of that of industrialized nations? The paucity of processing and packaging leads to food waste, spoilage, rot, and pathogenic microbiological growth. Read the histories of this country and the family farm orientation of the early twentieth century and learn of the poverty and inability to feed the farmers themselves, much less the nearby factory workers.
Did Americans really experience safer, healthier, and longer lives when fresh, nearby, farm-raised commodity foods and ambient distribution were the order of the day? The answer is that without the protection of plastic film blankets and their like, food infections and intoxications resulted from microbiological contamination and were significant health hazards. Was the quality of life for the majority of Americans who subsisted on local farm outputs safe? Where were the bananas, coffees, chocolates, artisanal cheeses, juices, and sauces—all made possible by this century’s processing, packaging, and distribution infrastructure—that entertain our meals today?
Do we have statistical evidence of our assertions as to the interface of packaging and food safety? No, but the anecdotal evidence is as transparent as any in our chronicles of food. Canning, with its conservative excess heating for safety and double-seam steel for protection and shelf life, waxed paper for wire-bound wooden crates, or packing products in ice—this was food safety in the “good old days.”
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Food safety today is a vastly different concept from that pre-food and food packaging technology era, save for those advocates for reverting to local farming. Food safety is an intimate marriage of initial quality; temperature-controlled distribution (still imperfect but progressing); controlled processing; and packaging. Note the operative word “controlled,” meaning that most technologists know much about what interferes with safe quality delivery and institute practices that maximize quality retention and minimize contamination in the total system.
The Barrier Called Packaging
It is easy enough to state that food safety begins with protection against the environment as the key. By enveloping the food with a barrier material and carefully sealing the structure, entry of environmental microorganisms, oxygen, moisture, and other contaminants that might introduce some element unhealthy to humans is effectively blocked.
It is never possible to achieve perfect barriers. The goal is simply to improve shelf life. Even steel, aluminum sheet, and glass are not perfect barriers since some gaseous components, however few, can permeate through the edges. These hard package materials successfully exclude particulate contaminants, but plastic and metal film can achieve the same result at a much lower cost.
Thus, when we read this dissertation correctly, all valid package structures effectively exclude external environmental biological entities, fostering safety from that most significant of perspectives. Of course, exclusion after packaging is but one phase of food safety, since, if the product has not been processed to minimize the biological, chemical, and physical vectors prior to or during packaging, all the physical protection against their subsequent entry is of little value. Further, if the distribution environment (read temperature and moisture content), are not within strict limits, barrier is of little or no assistance.
What then of the allegedly toxic chemicals in food package materials, which have received so much attention in recent months? Since the advent of plastics as the basis for package structures during the mid-twentieth century, much has also been written and discussed on their toxicity, with allegations far more terrifying than any in the 21st century.
We recite the Delaney Amendment to the Food, Drug, and Cosmetic Act, which has finally been effectively shelved after its focus on trivia has been recognized. Who wishes to remember the fight alleging that one molecule of the hydrogen peroxide sterilant in aseptic packaging would lead to a cancer epidemic? Do you recall reading in your history books of vinyl chloride—banned forever, but in contact with about half of our fresh meat with no fatalities reported to date? Or its cousin polyvinylidene chloride (PVDC), one of the most inert chemicals on the planet? Or even the synonym for “inert,” Teflon, hardly even used in package materials, but implicated as a lipid barrier contaminant? Does anyone alive today recollect the acrylonitrile debacle of the 1970s in which this alleged carcinogen was finally not found in packaging—after being banned? The chronicles of food packaging abound with accusations that have later been proven false or invalid or even inane in the annals of food safety.
Sound food packaging has saved infinitely more lives through its exclusionary properties than all the accusations from those who would wish to ban or limit its applications as one of the primary preservation tools we hold in our quivers. Think of the gross differences in morbidity rates in countries suffering a paucity of food processing, packaging, and distribution infrastructures vs the rates in the United States and Canada.
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In simple terms, understandable to all competent food and food packaging scientists and technologists, packaging is only one indispensable foundation of food preservation and safety, of some value alone, but significantly more useful in synergy with the other indispensables.
If the barrier function is so important to protection, can other functions be introduced that will render the package structure even more effective in enhancing food safety? Might food package structures repel vectors of deterioration much as Superman might do with his never-rip cape? As much as we have thought about microbial repellents, we have not yet extrapolated to that level of creature. . . but wait until next year?
And, of course, breathes there a food packaging technologist who has not been exposed to active packaging and it subsegment antimicrobials? (For those of you who have been immersed in Stanley Cup action or other engrossing activities this summer, read the last few packaging columns in Food Technology.) Indeed, many antimicrobials in vitro have been demonstrated capable of spoilage and pathogenic antimicrobial effects. (When you attend the 2010 IFT Annual Meeting, you can expose yourself to dozens of presentations on such diverse materials as chitosan, a lobster shell extract; nisin, a bateriocin; allyl isothiocyanate (AIT) from horseradish; grapefruit seed extract; and more). When incorporated into package structures, however, some or most of the desired safety values seem to evaporate, figuratively. (If this were literal, they might have some great value.)
Food safety depends on an integration of technical inputs from a variety of sources, none of which are capable of unilateral functionality. It is therefore imperative to blend the pieces into a meaningful whole that can maximize food safety while retaining food product quality. Packaging helps a lot, but not yet as much as we might hope.
by Aaron L. Brody, Ph.D.,
President and CEO, Packaging/Brody Inc., Duluth, Ga., and Adjunct Professor, University of Georgia