Combat-Ready Kitchen: How the U.S. Military Shapes the Way You Eat (2015)

PLASTIC PACKAGING REMODELS THE PLANET

LUNCH BOX ITEMS #6 AND #7: SARAN WRAP AND JUICE POUCHES

“Girls! It’s 9:30 p.m.! Time for bed.” I save my Word document, shut the window with the—blush—Daily Mail, and put the stack of bills next to my laptop as a reminder to pay them tomorrow. (Computer, olefin carpet, cables, phone.) The front door creaks open. “Smokey! Kitty!” Eloisa, our youngest, stays up worrying unless the cat’s in. She runs upstairs to join her sister Dalila in the bathroom, where they stand together at the sink, brushing their teeth. (Toothbrushes; all those three-quarter-empty shampoos, lotions, and sprays; latex house paint; PVC plumbing.) I climb the three flights of stairs from my basement office to their room in the attic. Tucked under hibiscus-print quilts, they are both reading. Smokey lies across the foot of Eloisa’s bed, purring. Across the hall, my mother sits in an armchair, also reading. In the kitchen, we hear clinking and clattering. It’s trash night, and my husband is wrestling closed two large garbage bags, regular and recycling, filled mostly with the detritus from the river of plastic that runs silently through our house. (Plastic bags, metallicized bags, plastic films, laminated foil-and-plastic pouches, plastic-coated cardboard, plastic clamshells, plastic tubs, plastic bottles.) I plant a kiss on one soft cheek. “Good night, sweetie.” And then the other. “Good night, sweetie.” Later, I’ll text our college-age daughter the same thing. As I head downstairs, Jorge comes in, the tumbler clicking into place as he locks the door behind him. Another day ended, and we’re all safe. Benediction.

IF YOU’D TOLD AN EGYPTIAN MORTICIAN or a Babylonian boat maker that the twentieth and twenty-first centuries would be built of pitch, he would have guffawed heartily. Ancient civilizations collected sticky black bitumen, or asphalt, which welled up spontaneously in rocky Middle Eastern outcrops, and put it to use as paving for roads, mortar for building, glue, weatherproofing, and an embalming agent. But beyond that, the sludge wasn’t good for much. In fact, no one paid petroleum much mind until 1879, when a German engineer, Karl Benz, successfully harnessed a combustion engine to a carriage. Suddenly consumption of crude oil, the refining of which had been invented in 1848 by the Scottish chemist James Young, who noticed that heat caused oil to seep from the roof of a coal mine, skyrocketed—and kept climbing, in the United States increasing more than two hundred times during the twentieth century.¹ Still, after the precious fuel had been distilled, there was the issue of sludge. Then oil company engineers, in an effort to beat the competition with better-running gasoline, began to further refine crude petroleum by separating the spontaneous-combustion-prone heavier hydrocarbons. These waste products eventually became the signature material of the modern age: plastic.

There are some people who always seem to land on their feet. The Austrian chemist Herman Mark, the father of polymer—colloquially, plastics—science, was one of them. This is not so much luck as skill—one that combines unceasing work at one’s profession, the careful cultivation of connections, and the ability to make life-changing decisions in an instant. Mark had all this and more: he was athletic, courageous, and optimistic, a formidable man who would be tested and triumph not once but several times during his life.

Just out of his teens, he managed to become a decorated soldier and earn a doctorate—rising early even if he’d drunk his companions under the table the night before. Wounded by shrapnel in the ankle as a young Austrian army soldier in World War I, he read chemistry textbooks as he recovered. Later in the conflict, he was captured, but after six months bribed his way to freedom to visit his sick father. Once at home in Austria, Mark matriculated at the University of Vienna, breezing through his much-postponed Ph.D. in chemistry in less than two years. He was promptly invited by Fritz Haber—whose discovery of how to synthesize ammonia revolutionized both agriculture (fertilizer) and warfare (explosives) and whose development of the deadly chlorine gas used in the war gained him the epithet “the Father of Chemical Weapons”—to work at the newly formed Kaiser Wilhelm Institute for Textile Fiber Research in Berlin. There, the young scientist quickly mastered X-ray crystallography, a technique then in its infancy in which the structures of atoms and molecules are mapped by bouncing high-energy electromagnetic waves off them.

Mark’s newfound laboratory skills allowed him to settle one of the most heated controversies in his field. Chemists had made huge advances during the nineteenth and early twentieth centuries: identifying the elements, decoding atomic structure, and developing models for how molecules bonded. But the next step, understanding how these building blocks were assembled in more complex arrangements, had been hobbled by one man, Nobel Prize winner Emil Fischer, who’d dismissed out of hand the possibility of very large molecules. This eventually led to an intellectual showdown at the 1926 annual meeting of the Society for Natural Science and Medicine in Düsseldorf, Germany. First up were the organic chemists Hans Pringsheim and Max Bergmann, who argued that the phenomena were, in fact, colloids—clumps of floating but unbound particles. Then came Hermann Staudinger, the original proponent of the concept, who demonstrated new data on rubber and synthetic polymers and insisted that they, protein, and cellulose were all macromolecules. The audience remained unconvinced. The decisive moment came during Mark’s presentation in which he shared his X-ray diffraction studies of cellulose, the compound that lends rigidity to plants, comparing it with the recently discovered structure of graphite and diamond, a large network held together by covalent bonds. At the end he affirmed that cellulose could, in fact, be a macromolecule. “Terrifying,” said Richard Willstätter, chair of the debate. “But, on the basis of what we have heard today, it seems that I shall have to slowly adjust to this thought.”² Shortly thereafter, Mark left the Kaiser Wilhelm Institute and accepted a dual position at a Frankfurt university and the I. G. Farben company, a German chemical conglomerate, where, as the head of a laboratory on fiber and film, he was charged with developing synthetic textiles, as well as working on the first synthetic rubber and polyvinyl chloride.

Synthetic polymers replicated in the lab—and later the factory—what chemists were observing about natural polymers: that they were immense chains of repeating units linked by a backbone of carbon atoms. In nature, macromolecules come from living creatures. In the lab, they do, too—except the creatures lived sixty million years ago. Most man-made polymers are created from hydrocarbons, the one-thousandth of dead plant and animal matter that, instead of entering the food chain, escapes or is born into the ocean. There, this organic debris is pushed slowly, very slowly, deep into the earth, where high temperatures energize the molecules and high pressure forces them closer together. The resulting new substances are hydrocarbon monomers—the building blocks of synthetic polymers.

Aside from fuel, these monomers are actually one of the important by-products of the modern oil refinery, an eerie maze of hissing and thumping tanks, tubes, valves, and engines, often occupying hundreds of acres or more. The machinery may look complicated, but the principles it employs aren’t. By heating crude oil—and, as was discovered later, applying pressure and chemical catalysts—engineers take advantage of the different boiling points of the component hydrocarbons, separating them in various chambers. The remaining heavy molecules are then “cracked” into small ones for reprocessing. There are literally thousands of different types of hydrocarbons, each with its own distinct molecular weight and configuration and, thus, distinct properties. Synthetic polymers, or plastics as most people call them, are made by taking a lot of these identical monomers and then linking them all together with heat and/or chemical catalysts.

Mark’s work at I. G. Farben came to an abrupt halt in 1932, when, nervous about the increasing influence of the Nazi Party, the plant’s managing director suggested to the half-Jewish Mark that it might behoove him to look for a new job. Obligingly he decamped back to Austria, transplanting his research projects to the University of Vienna, where he set up the first polymer science curriculum. But Mark’s return to his homeland was short-lived. In early 1938 he was arrested by the Nazis, and only got away with a bold plan: he purchased his passport, which had been confiscated by the police, with a year’s salary, turned the rest of his life savings into platinum clothes hangers, and loaded the family in the car for a Swiss “ski vacation.” He then wrote to a Canadian paper manufacturer that had expressed interested in employing him in its cellulose research lab. The family spent two years in a mill town sixty miles west of Montreal, until Mark, again taking advantage of a business contact, arranged for an opportunity to start anew through a consulting job with DuPont and an academic position at the Polytechnic Institute of Brooklyn.

The appointment would usher in the Plastic Age.

Until the late 1930s, the material world was a dangerous place. Most durable objects were heavy and sharp, made of wood, glass, ceramics, and metal, while the few disposable ones were made of paper, wax, and cloth. World War II changed all that. The enormous demands the military had for materials—for everything from shoe eyelets to tires to tents—and for which, in some cases, such as with natural rubber, supply was interrupted by the Japanese, spurred a frantic scientific race for substitutes. One of these was the synthetic rubber program, the second largest after the Manhattan Project, and until the announcement of the atomic bomb, considered to be “the greatest technical achievement of all time.”³ The research was conducted by, among others, the United States Rubber Company, the University of Chicago, the University of Minnesota, the University of Illinois, Cornell, Princeton, and the Polytechnic Institute of Brooklyn. But although Herman Mark had worked on the two fake rubbers, Buna-N and Buna-S, when they were invented in Germany in the 1930s, he was only peripherally involved in the project.

Mark had more interesting fish to fry: developing artificial materials to replace the traditional ones used in the prosaic items of daily life, an endeavor that would earn him the nickname the “Father of Polymer Science” and spark the transformation of the Polytechnic Institute of Brooklyn into the premier polymer research organization in the nation (at the time, the only one). “When I looked from Canada on the United States,” said Mark, “the question was whether there was any work on polymers going on in academia. The answer was: scattered, not organized. Speed [a researcher at the University of Chicago] worked on the synthesis of new monomers and new polymers… . There was North Carolina; work was done there on fiber strength, fiber elasticity… . National Bureau of Standards was working with rubber, but not with fibers; no synthesis, not the whole thing… . Our idea was that we were going to have an organized program here.”⁴

His ambitions dovetailed perfectly with those of the government. According to a postwar National Institute of Standards and Technology report, “By 1941 sufficient knowledge was available to set up emergency specifications utilizing plastics in place of scarce metals in many Government purchases. With Navy and NACA [NASA’s predecessor agency, the National Advisory Committee for Aeronautics] funds, research began on the properties and fabrication of these strong lightweight materials… . Among new plastic products sent for testing were helmet liners, resinous coatings used for protection of steel hardware, bayonet handles, Bureau-designed binocular housings, bugles, canteens, clock housings, compass dials, raincoats, food packaging, goggles, insect screening, shaving brushes, and aircraft housings.”

Mark’s first Polytechnic post was at the Shellac Research Bureau, something of a backwater. That switched once Pearl Harbor was attacked and the war officially began; Indian and Thai imports of the insect resin, often used to insulate electrical fixtures, were halted by the Japanese. Finding a synthetic version became urgent. “We got a tremendous lift immediately,” explained Mark, “because we were working on products and problems which became extremely important for the conduct of the war… . Permeability and impermeability of films; synthesis and characterization of synthetic rubber; and Cordura [a synthetic fabric developed by DuPont]. With these three things we had very large programs from the Army and from the government; several million dollars.”⁵

Mark quickly became part of the university’s inner circle, one of three wartime research magnets—the others were specialists in aviation and electronics—who together increased Polytechnic Institute of Brooklyn’s sponsored research program almost tenfold between the years 1942 and 1945. Those contracts, many of them restricted, were with the Office of Scientific Research and Development (OSRD), NACA, the Navy Research Bureau, and the Quartermaster Corps. (In 1944, the funding the Polytechnic Institute of Brooklyn received from the Quartermaster Corps was more than that for any other contractor, including such illustrious names as the University of Chicago, Columbia University, General Electric, Arthur D. Little, MIT, the Mellon Institute, and Monsanto.)⁶ Each of these military agencies had a pressing need for Mark’s—and his fast-growing stable of polymer experts’—scientific knowledge and technical know-how to create or perfect new fibers, films, and rubber for the war. But “the main project that Mark was running … was working on polymers that were of use in films and coatings,” said Bruno Zimm, one of the chemists who worked for him.⁷

A polymer can be millions of times as big as water, carbon dioxide, and other common molecules. The importance of its size can be understood by imagining shaking a cardboard box full of marbles and one full of beach balls. Which move around more? Marbles. Polymers, because they are so big and bristling with shorter side chains, don’t shift position as readily as smaller molecules, and tend to jam up, reducing flow. This accounts for their three most important properties: viscosity, elasticity, and strength.

These characteristics are affected by heat; how and how much depends on the type of polymer. For example, thermoset plastics can be locked into permanent position by cooking, which causes irreversible cross-linking of their side chains. Thermoplastics, on the other hand, can be softened and remolded many times; their side chains slide by one another without catching much. Polymers can be used singly or in combination to increase strength and flexibility of the end material. Plasticizers, other much smaller petroleum-based molecules, are commonly added as well. Think of them as the marbles in the example above. If you mixed the marbles with the beach balls, they would push the beach balls farther apart, so the oversize inflatables move around more easily. Plasticizers lower the glass transition temperature, the point at which all flow stops, so most polymers are flexible at room temperature or below. With films, which are thermoplastic, the resulting resins are then treated in different ways—blown, rolled, stretched, and coextruded (combined with other polymers in layers)—to achieve the desired hardness, flexibility, vapor and other gas resistance, longevity, opacity, and strength.

One of the polymers worked on by Mark and his team was an oily green substance that had been discovered almost a decade earlier in a Dow Chemical lab, when a technician found the residue at the bottom of a beaker where he’d been making a dry-cleaning chemical from chlorine. “It was very difficult to dissolve,” said the accidental inventor, Ralph Wiley, who almost immediately took out a patent. “There was no chemical that would touch it.”⁸ Saran, a copolymer—two monomers blended together into a single structure—of vinylidene chloride and vinyl chloride, is both tough and extremely resistant to water and oxygen. Its commercial debut was as a fiber for lawn chairs and train seat covers in the late 1930s, but a year or two later, another technician, Wilbur Stephenson, developed a method for creating a vinylidene film.

The army immediately saw Saran’s potential as a protective barrier, spraying it on engines, guns, and metal parts to prevent corrosion from water and salt during shipment overseas on open decks. Later in the war, when it became apparent that the various combinations of cellophane (a shiny, stiff film from plant fiber), waxed paper, and foil were inadequate for shielding rations from moisture, the Quartermaster Corps began to explore the possibility of making a food-contact film from Saran. To do so, however, it would have to find a way to make this auspicious material flexible and keep it from becoming brittle and opaque as it aged.

The project was carried out at both the Polytechnic Institute of Brooklyn and the Dow Chemical Company, which to this day dominates the market for the monomers for both vinylidene chloride and vinyl chloride. At the chemical company, the project was led by Raymond Boyer of the Physics Laboratory. “The other job that took most of my time dealt with the light and heat stability of Saran—which we called at that time ‘Ventyloid,’” explained Louis C. Rubens, a chemist in the lab. “Ralph Wiley had been working on Saran. Light and heat stability were already identified as the key problems of that material. Two colleagues tackled that problem. Lorne A. Matheson and Ray Boyer. They knew it was photo-degradation… . But they really didn’t know how to prevent it… . Photodecomposition was a key problem then, as far as Saran was concerned… . It was primarily an Edisonian research program that was initiated by Boyer and Matheson.”⁹

Into that Edisonian fumble in the dark, Herman Mark inserted some scientific scaffolding. As Dr. R. H. Boundy, the company’s vice president for research and development, described it, “he [put] a theoretical base under the things we in industry were doing by trial and error.”¹⁰ Among the restricted projects conducted at Brooklyn were various studies on vinyl polymers and copolymers, the family of plastics to which Saran belongs. A goal of this research was “to act as a stimulus by supplying new fundamental ideas which may eventually be utilized in a practical way by industrial laboratories… . The Laboratories have done much work with the overall aging characteristics of plastic films including such problems as plasticizer migration, sunlight and atmosphere degradation and freedom from blocking.”¹¹

In 1946 the Chemistry Department of the University of Buffalo held a symposium to disseminate the work on vinyl polymers and plasticizers during the war and invited chemists from both Polytechnic and Dow. In his opening address, E. F. Izard of DuPont lauded the government’s effort to come up with new materials for flexible sheeting and films to replace rubber and cellophane, which were either unavailable for or inadequate to wartime tasks.

The critical military requirements soon made it evident that only polyvinyl butyral, polyvinyl chloride, and copolymers of vinyl chloride with other vinyl compounds [such as Saran], would be suitable substitutes [for flexible sheeting]… . [A] very far-reaching and rapid evaluation of compounds suitable for these new uses had to be carried out. This required the cooperative efforts of many industrial firms, Government laboratories, and Government-sponsored projects at universities… . These new products as films were admirably suited to many new uses resulting from war requirements.¹²

The instrumental role of the military in creating and perfecting these new plastics was also noted by the Quartermaster Corps itself. “Since the Army must ship and store such a wide variety of foods under adverse conditions for long periods of time, the films used for packaging must meet rather rigorous requirements… . Colonel Denny [from the Office of the Quartermaster General] pointed out that no one product can fulfill all of these requirements, but that the object of the Section’s research is to comply with these military characteristics. He stated that recent work with Saran and thin nylon films, as well as plastic coated foils shows promise.”¹³

Boyer and Dow were so eager to stake their claim that they filed a patent for “vinylidene chloride compositions stable to light” on May 4, 1945,¹⁴ just four days after Hitler committed suicide, when the end of the war—and the restricted research program—was imminent. Saran wrap first appeared in the commercial market in 1949, as a tool for institutional and restaurant kitchens. (Ultimately, its industrial use was limited by the extremely narrow range, some twenty degrees, of its heat-seal temperature.) The final formulation, to give it flexibility while making it more impervious to heat and light, was a mix of 15 percent vinyl chloride and 85 percent vinylidene chloride with three separate plasticizers—one pound for every two of polymer. The resin was blown and then rolled to a thickness of no more than one-hundredth of a millimeter.

Four years later, Dow made its initial foray into the consumer market, introducing its new film with the advertising copy: “Only Saran-Wrap will keep it so fresh, so long … so easily! It clings by itself, … It’s moisture-proof… . It’s crystal-clear.”¹⁵ Raymond Boyer was heralded as its inventor, eventually being inducted into the Plastic Academy’s Hall of Fame for his “heat and light stability studies, instrumental in the development of SARAN,” and earning this line in his National Academy of Engineering biographical sketch, “[Boyer’s] work with plasticizers was instrumental in the development of Saran.”

On the other hand, Mark, his crew of chemists, and the Quartermaster Corps were discreetly removed from the pedigree. Said Boyer of his colleague, “Professor Mark almost deliberately tries to stay in the background where credit is concerned on any commercial matter. Hence, things like joint patents and joint publications bearing his name are virtually nonexistent. To hint at contributions would only serve to weaken existing patents which do not bear his name.”¹⁶ Zimm confirmed the self-effacement of Polytechnic and the Quartermaster Corps. “We never published any of it in the open literature. There was a big report written at the end of the project describing the things that were found. But never any papers. We found a number of things which have since been verified by other people.”¹⁷

By the 1960s and 1970s, Saran was the leading household wrap, so much so that its trademark became the name for any clear, thin, and clingy plastic wrap, but worries over the release of chlorine gas during incineration and migration of plasticizers into food—particularly phthalate esters, the most commonly used and the dominant one in Saran—began to concern public health officials and activists. The leaching from films wasn’t news to the army; in 1949 the Quartermaster Corps oversight committee on plastics had discussed “the problem of plasticizer migration and its relation to bleeding of the plasticizer onto asphalt packaging papers [a waterproof laminate of asphalt between two layers of paper],”¹⁸ but they seemed strangely unconcerned about its inward migration into the food itself, and had gone ahead anyway. In 1997 Dow sold its Saran brand to S. C. Johnson & Son, which in 2004 discreetly changed the film’s formulation to the less disintegration-prone linear low-density polyethylene (LLDPE).

KNOWING WHAT THEY—and what all chemists—knew about plastics, it appears folly that, in the early 1950s, army packaging experts proposed to find a way to heat-sterilize food and then store it for very long periods in plastic wrappers. The three materials humankind had historically used for cooking or storage vessels—ceramic, metal, and glass—soften or melt only at extremely high temperatures (a couple of thousand degrees Fahrenheit) and are either relatively inert, interacting very little with their contents, or have coatings that keep them from doing so. Not so plastic. Most common synthetic polymers used in food packaging soften at 200°F to 300°F, and as far as migration goes—suffice to say that as the molecular equivalent of a plate of spaghetti (the polymer) swimming in sauce (the plasticizer), it’s easy come, easy go. It’s a problem that has dogged the use of plastics in food packaging since the beginning.

In the early 1950s the Quartermaster Corps delivered a wish list to its packaging division: containers that you could manipulate in subzero temperatures, packaging for frozen foods that wouldn’t disintegrate, barriers for dehydrated foods so that water vapor and oxygen couldn’t penetrate them, and rations that wouldn’t be the source of friendly fire wounds and casualties when air-dropped. For a while, each of these problems was worked on separately, but the solution to all quickly converged into one word: plastics. Was it possible to replace the sturdy metal cylinder, which, since the earliest days of canning, had been the favored cooking and storage vessel for moist, shelf-stable foods, with a flexible plastic pouch? In typical never-say-never fashion, the army put their heads down and got to work.

The first step was to review all the available materials and to subject them to conditions simulating that of a retort-processed ration—steam-cooking for three to fifteen minutes at 250°F, random mistreatment, and then abandonment for months. (A retort machine is an industrial canner that subjects multiple cans, jars, or pouches enclosed in a tank to high heat, in the form of hot water, spray, or steam, until their contents are sterilized.) The Quartermaster Food and Container Institute research team, led by Frank Rubinate, quickly found that the best candidate—one that wouldn’t melt, harden, discolor, or disintegrate—was a combination of a layer of vinyl, a layer of aluminum foil, and a layer of polyester film. “It was really a lot of standard packaging techniques, but they had to perform at a greater level of reliability and completeness than before,” explains Rauno Lampi, a food scientist who worked on the project at Natick from 1966 to 1976. “We borrowed from both the canning industry and the flexible packaging industry.”

But from there, the army was stymied—it was a new technology, so to gear up, production capabilities would have to be inculcated in industry. And what better way to do that than to hold a conference, with the lure of revealing the goodies developed for the government’s research program to companies that were always on the lookout for the next big thing? The attendee list read like a Who’s Who in the American food and plastics industry: Aluminum Company of America, American Can, Beatrice Foods, Continental Can, Dow Chemical, DuPont, Eastman Kodak, Gerber Baby Foods, Goodyear Tire & Rubber Company, Kaiser Aluminum, Libby, Monsanto, Oscar Mayer, Pillsbury, Procter and Gamble, Quaker Oats, Reynolds Metals Company, Swift, Union Carbide, U.S. Industrial Chemical Company, and W. R. Grace and Company were just some of the almost sixty major corporations there.

“It should be very encouraging to the Quartermaster to realize that industry will be vitally interested, not only from a standpoint of national responsibility, but from a selfish viewpoint,” commented one presenter, an equipment manufacturer, at the 1960 Conference on Flexible Packaging of Military Food Items. “Many of the food products, processes, materials and machinery which the Quartermaster requires can be used in the future by industry. The items with which he is dealing will be of great interest to the general public as items which they can consume as well as the military man.”

Resolving all the technical issues—from seals that burst, processing equipment that was designed for cans, dribbly filler nozzles, and separation and migration of the adhesives used to hold together the three layers—took the army roughly two decades from the inception of the project, and resulted in innumerable innovations in the packaging industry, some of which are just now becoming industry standards, such as using ultrasound, a rapidly oscillating pressure wave, instead of heat to create seals on premade pouches. “It was a case where the objective and the momentum of the government drove all the players… . There were many examples of research grants coming from the Natick group into private industry to develop composite materials, the components, the equipment that actually processed these filled pouches and sterilized them. The whole system was envisioned and [then] stimulated by the government research funds,” says Tom Dunn, a thirty-year flexible-packaging industry veteran and a consultant.

“But this big missing link in all of this was the adhesive to hold these individually necessary elements together into a single, synergistic packaging material,” he continues. “It had to have the properties of (1) being able to withstand the high temperature and (2) being able to withstand the pressure inside the pouch, and then maintain integrity in the field with all the abuse it would encounter. While at the same time, what’s not so obvious is that the overreaching concern on the part of all parties was the migration of the chemistry of these adhesives from the interface between the aluminum foil and the heat-seal layer through the food and into the food itself.”

The problem of leaching of either small unattached chains of the polymer or the freewheeling plasticizers, which are liable to migrate out anyway, a tendency that increases with temperature, had been recognized by military packaging experts from the earliest days of polymer research during and immediately after World War II. With the flexible-retort-pouch project, once a set of materials had been selected, the Quartermaster Food and Container Institute commissioned outside safety studies, including one on migration of plastic components from foil-plastic laminates after high-temperature processing conditions. The research, conducted by Marcus Karel and Gerald Wogan at MIT in 1963, found that polyolefin-based laminates met FDA standards, but not those based on vinyl polymers, and that the residues from the vinyls “appeared to be aryl esters, probably phthalate.” They also found that for both types of materials there were “more extractables [leached materials] from heat-sealed films.”¹⁹ The only other testing of the migration of toxins through the laminate was done by Pillsbury three years later, which concluded by calling for more studies, but basically gave the new materials a clean bill of health. Perhaps not coincidentally, Pillsbury was a member of an industry consortium led by Swift to which also belonged Reynolds Metals and Continental Can, manufacturers of the custom-designed three-ply food wrapping.

But the plastic migration problem was overshadowed by the technical challenges the Natick Center faced in turning the concept into something that could and would be produced by the food industry, and was not given another thought until 1976, when the army finally felt it could make the case to the FDA to approve the plastic food pouches for use in soldiers’ rations. “Technically, we could have approved it for military use without,” says Lampi. “But it would have been politically dumb not to get their approval. And that would also help the commercialization.” The initial petition was rejected. The FDA was concerned about a previously unregulated carcinogen, toluene diisocyanate, a component of the adhesive. “We ran into a problem in the late [1970s] with bags intended to hold food during heating (boil-in-bags or retort pouches),” wrote an FDA official later. “At the higher temperatures, some of the laminates were insufficient barriers.”²⁰ Meanwhile, Natick and its contractors did an end run around the adhesive issue by opting for a heat-fused laminate; the MRE with its plastic-pouch-encased entrées became standard soldier fare starting in the 1980s.

Today, the flat, plastic “flexible cans” are used widely in the Asian and European markets, but are just catching on in North America. Lampi attributes this to the deep entrenchment of the American cold chain, which moves food efficiently from factory to your fridge with nary—except for your car—an interruption in its ambient temperature of just above freezing. Dunn also points out that U.S. companies have a well-developed manufacturing infrastructure, and, unless there is a compelling reason to abandon it, will continue to use their existing equipment. But he predicts that the minute a food processor moves abroad, it will dump its old canning facilities and embrace the pouch, which is cheaper, results in better quality, and produces merchandise that can be sold to a global market, as has already happened in the shelf-stable tuna market. These products—lemon-pepper tuna, heat-and-serve fajitas, the sauce packets in frozen and ready-to-eat entrées, juice pouches—are already appearing with increasing frequency on supermarket shelves.

The FDA has approved them, the market has accepted them, so now we should feel safe eating food cooked and stored in flexible pouches, right? Not so fast. Carcinogens may not have been found to leach into the food from the packaging, but that doesn’t mean a lot of other things, such as the unbound monomers and plasticizers—principally phthalates, such as the ones Marcus Karel noticed back in 1963—aren’t leaching into our food. The FDA’s old-school toxicology still uses cancer as the gold standard: a substance triggers regulation only if it contains a known or suspected carcinogen, or is present in the food at concentrations greater than 0.5 parts per billion, a policy that was itself adopted in response to the ever-present low levels of chemicals that migrate from packaging. (This also gave rise to the exemption of well over one hundred substances, from epoxy curing agents and adhesives to antimicrobials and perchlorate, from the need for agency approval if they are present in food in those proportions.)²¹

In 2008 Congress passed and President George W. Bush signed into law the Consumer Product Safety Improvement Act, banning three phthalates—DEHP, DBP, and BBP—from children’s toys. All three are used in food packaging. As part of the hearings on the issue, Norris Alderson, associate commissioner for science at the FDA, testified that “FDA-authorized uses of phthalates include uses in flexible food packaging” and, while recognizing that there was a “potential health risk,” disavowed the need for regulation because “such food contact uses have been greatly reduced or eliminated through the replacement of PVC and PVDC [Saran] polymers with other polymers.” His remarks concluded, “If our review indicates that existing data no longer supports the continued safe use of these materials in food contact material, FDA will take appropriate regulatory action to remove these materials from the marketplace.” To date, although DEHP was banned from medical bags and tubing, no action has been taken on phthalates in food packaging. Yet in 2012 the Environmental Protection Agency (EPA) was so alarmed by the sea of phthalates in which we now live—besides food, they’re found in personal care products, consumer products, toys, household dust, and soil—that it issued a Phthalates Action Plan, under the Toxic Substances Control Act, “based on one or more of the following factors: their presence in humans; persistent, bioaccumulative, and toxic (PBT) characteristics; use in consumer products; production volume.” Food, according to the EPA, is the number one source of exposure.

Evidence against the plasticizer is mounting. Numerous studies, many in Asia where there is more use of polymer-packaged shelf-stable foods, have found high levels of phthalate migration into food and a high blood level of phthalate metabolites (the by-products of the body’s breakdown of the ester), particularly in children. They have been shown to cause reproductive disorders in laboratory animals and are linked to endocrine disruption, such as sperm damage in men,²² and lower IQs in children.²³ An Italian project found migration of adhesive components, including phthalates and isocyanate, the chemical the FDA was concerned about in the army’s original retort pouch, in about a quarter of laminates,²⁴ and a recent metastudy by Korean researchers found that babies fed food from ready-to-eat plastic pouches (little brother of the MREs used for soldiers) had the highest estimated daily intake of phthalates adjusted for body weight of all subjects in the study—and that was from just one serving.²⁵ A diet loaded with plasticizers may be an acceptable risk for soldiers, for whom the ability to throw a squishy package into a bursting backpack and tear into it on a moment’s notice is a true advantage, but maybe not for the rest of us, especially those who can’t make their own choices.

ANYONE WHO’S EVER CLEANED UP A CAMPSITE knows a couple of people can generate a shocking amount of trash. That goes decuple for warriors stationed in the field and subsisting on combat rations. Each MRE contains a third of a pound of solid waste, mostly plastics and cardboard, and a recruit consumes three MREs per day; the military generates a total of thirty thousand tons of ration packaging waste annually. All of this could be recycled or turned into fuel—except for the laminated pouches, which include a foil layer and thus permanently sideline more than three million pounds of packaging material a year. Not only is the metal material unrecyclable, it adds manufacturing steps, is difficult to handle during production, is plagued by tiny ruptures, and causes problems with next-generation processing techniques. In a nutshell, foil is an expensive pain in the neck.

But the foil layer is there for a good reason. Aside from glass, which has obvious drawbacks, metal is the definitive barrier to water, oxygen, and other gases. Plastics may have smooth, shiny, and seemingly impenetrable surfaces, but in fact polymers transmit vapors; the rate at which this occurs depends on the type. For that reason, no one had ever considered an all-plastic replacement for the can. Until recently. In the late 1980s the promise of nanotechnology became a reality, making its debut in Toyota car parts. A decade later, the army decided to see if polymers filled with nanoscale particles might be an adequate substitute for the foil layer in laminated retort pouches.

To understand the world at the nanoscale (1-100 nanometers), skip the mind-boggling numbers. Just imagine human cells (10,000-30,000 nm), most of which (except for the freakish ovum) cannot be perceived by the human eye. If your cell were a house, its nanoscale contents would be about the size of appliances or smaller: a microwave-oven ribosome (25-30 nm) or a smart-phone protein (5 nm). The walls would be the cell membranes, lipid bilayers composed of stacked proteins and mobile lipids, which are porous to some hydrophobic molecules and have special protein channels or pumps—the equivalent of vents—for sugars (1 nm), amino acids (0.8 nm), nucleotides (0.9 nm), water (0.2 nm), salts, and other essential materials. Larger molecules (up to 500 nm) could enter by membrane enfolding—let’s call this a door. This permeable barrier system leaves bacteria (a hulking 500-5,000 nm) out in the cold, while admitting viruses (20-400 nm). Nanoparticles, because they are so small, enter human cells more rapidly than larger particles of the same material. (This characteristic has made them a hot research topic in the pharmaceutical industry, which hopes to exploit them for drug delivery.)

Most of the nanomaterials used in food packaging are not so much designed and built but broken down—through good old-fashioned industrial processes such as milling, etching, and burning. The most commonly used (and not coincidentally the cheapest) are clays, in particular one called montmorillonite, a relation of talc, which comes in tiny platelets that are one ten-thousandth the thickness of a human hair. Because the nanoclay particles are so small, they exhibit a large surface area, which bestows special properties: better interlocking, so nanocomposites are stronger than regular materials, and more nooks and crannies—the charming technical term for this is tortuous pathways—so oxygen, moisture, and other gases take a really long time getting through.

In 2002, working with two of the leading providers of nanoclays, Southern Clay Products, now a subsidiary of Rockwood Specialties, and Mitsubishi’s Nanocor, as well as several university contractors, Natick’s own laboratory, called the Polymer Film Center of Excellence, began to patiently put through their paces various polymers and fillers. “Nanotechnology was a huge buzzword within the army,” says Jo Ann Ratto, leader of Natick’s Advanced Materials Engineering Team (AMET). “We even had workshops at Natick constantly involved in nanotechnology and different applications for the warfighter. So we wrote a proposal, and, because of September 11th, we ended up getting our first proposal through [very quickly].” The AMET scientists zeroed in on ethylene-co-vinyl alcohol (EVOH), a plastic that has excellent oxygen—but not moisture—resistance, is recyclable, and is considered safe by the FDA for food contact.

They tried different formulations and different ways of producing the film—cast on rollers or blown by hot air. They did detailed studies of the new plastic’s structure. While the nanocomposite material was strong and had good resistance to oxygen and light, it allowed five to ten times as much water through as foil, and so was deemed inadequate to replace it—for now—in the food and retort pouches. (It also turned out to be a tasty treat for insects, so it must always be sandwiched between other layers.) But it could replace the low-density polyethylene meal bag that holds all the MRE components, using less plastic and, because of its superior moisture and oxygen resistance, allowing the items within the MRE to be more lightly wrapped.

As is ever true with the army, a setback only spurred a redoubling of efforts. The EVOH-based nanocomposite was advanced to the pilot stage and the water barrier improved by adding small amounts of another polymer, while Virginia Tech and Printpack, a major packaging company whose clients include Coca-Cola, Dole, Frito-Lay/PepsiCo, Hershey Foods, and Kraft, were contracted to review the work done so far on the new plastic and further reduce the water vapor transmission rate. (They were unsuccessful.) This only spurred a broadening of the nanotechnology net, with Natick inaugurating multiple follow-on projects. The Pliant Corporation was asked to develop a coextruded (produced all at the same time and adhered through melting) five- to seven-layer film; Appleton Coated paper company and Clemson University investigated new blending techniques (for example, one called “chaotic advection” folds two polymers together instead of mixing them, enhancing their barrier properties). Other companies worked on nanospheres, which reduce the amount of polymer needed because they incorporate air and lighten the film; bio-nanocomposites, which are made from materials such as starch, cellulose, lactic acid, and bacterial storage compounds, with the idea that these could be composted or buried; and barrier coatings. One or several of these approaches may have potential. “[The project] ended in 2012,” says Ratto. “At the time, we only did it for one food item, penne pasta for retort. And now we’re looking at all food items to have all-polymeric packaging… . I’d say in two to three years it could be in the system if performance is correct and acceptable.”

However, there is much that is still unknown about nanomaterials, particularly in the areas of safety and human health. Timothy Duncan, an FDA chemist from its joint academia-government-industry Institute for Food Safety and Health, explains, “Given the number of studies that cite food packaging as a likely endpoint for PCNC [polymer/clay nanocomposites] research, the number of researchers who have investigated these materials in shelf life or safety experiments using real food components is surprisingly small… . [While] PCNCs may represent the next revolution in food packaging technology, there are still steps that need to be taken in order to ensure that consumers are protected from any potential hazards these materials pose.”²⁶

As with phthalates, the FDA has not ruled on nanocomposites, instead requiring that nanoscale ingredients or additions to food-contact substances seek approval on a case-by-case base. In its June 2014 guidance for industry, only a couple of the thirty or so references addressed nanotoxicology.²⁷ The agency seems unlikely to take on the big—but increasingly urgent—questions anytime soon: How much do nanoscale particles migrate out of polymers? Once ingested, can nanoparticles enter living cells? Is their effect magnified many times over, as it is in inorganic substances, due to their shapes and high surface activity? Are they excreted or do they remain in tissue? And what kinds of conditions or diseases might they cause?

PROPELLED BY THE NEED to put traditional materials in service of World War II, to find cheap and plentiful substitutes for their everyday uses, and to protect rations delivered around the world in a variety of conditions, the U.S. Army encouraged the emerging field of polymer science to develop plastic food packaging, despite the obvious issues of poor temperature resistance and instability of its components. In the more than half century since Dow unleashed its—and, from behind the scenes, the Quartermaster Corps’—brainchild Saran film on the public as a way to keep food fresher, numerous other plastics have become commonplace in the supermarket and the kitchen. The Department of Defense has known since day one that plasticizers leach into adjacent materials, including food, but battlefield expediency appears to have trumped all other concerns. In the 1960s, it went ahead with an even more deterioration-prone scheme: heat sterilization and prolonged storage of food in polymer pouches. During the 1990s and early 2000s, the very period when the possible deleterious effects of the most common plasticizer, phthalates—on the endocrine system, on blood pressure, and even on IQ—were beginning to emerge, the army launched a new project exploring the replacement of the foil layer in retort pouches with nanoscale materials, although there is little to no toxicology data on the health effects of this size particle, which is perfect for entering and disrupting the human cell. In the use of plastics as food-contact substances, it may be high time we civilians abort the mission.