Will food science change the silhouettes of our fruits and vegetables?
I do not remember the canned goods or the freezer cases in the supermarkets of my youth as much a I remember the produce section. On one occasion, I recall, I stared in rapture at row upon row of lustrous, bright orange tangerines, each sphere a perfect replica of the next. The uniformity of the fruit gratified my eight-year-old eyes, and, at my urging, Mom bought some to take home. They were decent-enough specimens, but, as it turned out, I didn’t enjoy eating them nearly so much as I’d liked looking at them.
In the years since, I’ve come to understand the subtle tricks of the grocer’s trade and have found out that the American produce industry shares my interest in contour, color, and pattern. As a journalist, I learned that produce sellers have long banked on the often contested but widely held assumption that food shoppers incline toward symmetry and regularity of shape and appearance. Acccordingly, farmers, distributors, and retailers in this country have developed myriad methods for making sure that the size and shape of the fruits and vegetables they sell are as close as possible to what consumers are though to deem ideal.
It’s no secret, for example, that cross-breeding and grafting have been the industry’s methods of choice for molding produce into sameness, creating shapely hybrids that have played a part in pushing many older, more irregular-looking heirloom varieties off most supermarket shelves.
What’s more, before many supermarket apples, potatoes, and other items hit the produce racks at American grocery stores, they must pass muster at regional packing houses, where they’re sent toppling past multilane batteries of digital cameras linked to computers that instruct the machines to sort by size, curvature, and color. Only the most unblemished and uniform-looking survivors of such beauty pageants graduate to the shelves, while the rest must settle for juice boxes, jam jars, feed troughs, and all manner of processing and recombination. Packers then coat their supermodels in water-soluble shellacs and protective waxes before sending the product on to grocers, who align their fruits and vegetables in aesthetically appealing arrangements.
Though I’ve become accustomed to the reality of produce aisles packed with nearly identical apples and bananas, such displays can still have a hypnotic effect on me. But I didn’t realize how far crop science had advanced in the quest for perfect-looking produce until I happened to be flipping recently through a science journal called Plant Physiology and came across an arresting series of photographs. The images depicted sliced whole tomatoes superimposed on a background of Cartesian coordinates garnished with equations.
I paged back and began to read the article: in a breakthrough in genetic modification—a technique that scientists have already used, to much public outcry, in the development of hardier hybrids of corn, cotton, canola, and soybeans—plant geneticists and computer scientists had begun to isolate the groups of genes that control such factors as elongation, constriction, and blockiness in certain types of fruits and vegetables. Imaging software and molecular manipulation had enabled these researchers to experiment with the cultivation of custom-shaped produce.
What did this mean? In lay terms, it meant that the gradual decoding of various strands of shape-determinant DNA could not only five us seemingly faultless oranges and peaches but also transform our notions of what fruits and vegetables were “supposed” to look like. Packing giants like Dole and Del Monte would surely relish the prospect of square grapefruits and rectangular cherry tomatoes, all the better suited for sitting on conveyor belts and fitting into shipping boxes. And the genetic key to cylindrical, slice-ready tomatoes would no doubt interest the owners of hamburger joints everywhere. The manipulation of shape-controlling DNA would have no effect on flavor—which has itself been the object of seemingly endless experimentation—but I could easily envisage how customer-shaped designer produce, if marketed with enough sophistication, might seduce many supermarket shopper away from the real thing. How close, I wondered, had this new scientific discipline come to making such fantasies of idealized food real? And could this advance definitively spell an end to bumpy, blotched, lopsided—and, ultimately, unique-looking—fruits and vegetables? Esther van der Knaap, a 42-year-old assistant professor of horticulture and crop science at Ohio State University, is one of the leading innovators in the emerging science of fruit morphology, as her specialized field has come to be called (notwithstanding that vegetables are also the subject of her research). She and a team of seven assistants conduct their work in a group of low-slung brick buildings and greenhouses at a horticulture and crop science research development center in Wooster, Ohio.
On the day I met van der Knaap, she wore blue jeans and clogs and was seated before a computer screen in her laboratory. I pulled up a chair, as she explained a proprietary software program called Tomato Analyzer. This application, invented by van der Knaap’s team, can exhaustively calculate and catalogue the shape characteristics of any tomato on Earth—and also works perfectly well on strawberries, cherries, potatoes, and any other fruit or vegetable that can be sliced into cross sections.
Professor van der Knaap does most of her research on tomatoes, partly because they come in a relatively wide range of shapes and sizes, but today she happened to be working with a green bell pepper. She sliced the pepper lengthwise, laid one of the halves on a flatbed scanner, and watches as the outlines of the specimen emerged on the monitor.
She pointed to the upper portion of the pepper’s silhouette, which tapered to a double point. “There’s a little shape I find interesting,” she said. “Really cute. I’d like to know what controls that.”
Over the past several years, Tomato Analyzer has helped van der Knaap and her colleagues understand the shape variation caused by at least two fruit-shape genes: one of them, a strand of DNA they named Ovate, controls the expansion and constriction that create a pear shape; the other, called Sun, appears to determine elongation. Van der Knaap plans to extract a strand of Sun DNA from one of her tomatoes and transfer it to the leaf and root cells of an eggplant. To what end? “I’m expecting a more elongated eggplant,” she said.
“We do this research into tomatoes,” she continued, “but the goal is to understand shape diversity in other species. The more we know about the basic mechanism, the more we can apply it to just about anything.’’
At that point I couldn’t resist sharing my science fiction visions of square grapefruits and cylindrical tomatoes. Were such things possible?
“They’re possible, yes,” said van der Knaap. “The shapes are already out there. This can happen in nature; I just make it go a lot faster.”
The aim of the current phase of van der Knaap’s research is essentially to find out which genes yield certain shapes; the potential marketplace applications of her discoveries—as merely novelties for the retail sector, say, or procue customized specifically for the benefit of large-scale packers and distributors—remain to be seen. Still, van der Knaap told me, “there’s definitely industry interest in these genes. Shape really helps to sell a new product and create a niche market”.
She offered a couple of examples. “Watermelons are too huge for families these days. I would think there would be a market for very small watermelons, a cute little watermelon for a small family.” Or take heirloom tomatoes, she said: “They’re very disease susceptible. I could create a disease-resistant tomato with the shape and size features of an heirloom.”
Ohio State University has already applied for a patent for Sun DNA and may follow the lead of other horticulture institutes, including ones at the University of Nebraska, Cornell University, and the University of Hawaii, that have established relationships with major agricultural companies in the development of genetically engineered products. For now, however, the results of many of the OSU team’s experiments have yet to be fully revealed.
Does van der Knaap stand to profit personally from the possible commercial applications of her work? “I would get some money,” she said. “I’m the inventor.”
Later that day, as Professor van der Knaap led me from her lab station to one of her high-tech hothouses, I pondered anew the questions that had vexed me when I began reading about her work: Can the sublime attractions of a teardrop-shaped strawberry or a plump, round apricot really be reduced to an algorithm? Can our notions of aesthetic perfection be scientifically formulated? Before visiting van der Knaap, I’d put those questions to Carolyn Korsmeyer, a philosophy professor at the State University of New York. “It is a limited aesthetic tradition that assumed that the perfect is better than the imperfect,” she told me. “I think if one is focused only on creating the perfect fruit or vegetable, the tendency is to take the aesthetic value, the look of the thing, out of context. One of the contingencies of making meals is that you’re not in control of everything. Why would we want to control these things?”
And yet, in some ways, researchers like Professor van der Knaap appear to be taking great pains to eliminate those imperfections. As she guided me through the greenhouse, the building rumbled and buzzed and hissed with seemingly singular purpose; huge fans and industrial lights hovered above concrete floors spiderwebbed with plastic irrigation tubing. Near the entrance to the glass building, across from a wall-mounted pH monitor and an emergency shower and eye-washing station, loomed a tremendous steel door, reinforced by 20 steel bars. The door hung ajar on its hinges, revealing the insides of an iron vault that could have passed for a medieval torture chamber had it not been plastered with bright red warning signs.
“That is an autoclave,” said van der Knaap. The apparatus, she explained, functions as the ultimate kitchen garbage disposal, the final resting place for much of the genetically modified plant matter generated by the professor’s experiments. Once you’ve persuaded a fruit’s DNA to zig where it formerly zagged, you may not simply send the results to the local dump. After the scientific value of the experimental fruits and vegetables has been exhausted, the DNA-altered organic material is usually vaporized to oblivion, lest a new cultivar accidentally escape and become and invasive weed. Sure enough, just outside the autoclave a large wagonload of mud, flecked with plant cuttings, awaited its fate. “The soil must be steamed,” van der Knaap said, “to sterilize it.”
Beyond the autoclave lay numerous other greenhouses, each separated from the rest by internal glass walls and fronted by an aluminum sliding door stenciled with a number. Van der Knaap led me to the entrance of one of the rooms and pointed to rows of tobacco plants, the leaf cells of which had been infused with tomato DNA. I asked for a closer look, but Professor van der Knaap ushered meonward, explaining that those specimens were susceptible to contamination from an insect-borne virus that might be carried in from other parts of the facility. The slightest infestation, she cautioned, could set that particular shape-gene research back by months or years.
Van der Knaap did allow me to enter one room, where, she said, some of her genetically modified tomato plants had started to grow. As she slid open the door, the old childish excitement began to well up inside me. My mind suddenly filled with images of brave new custom-hewn fruit. But when we got inside there were no tomatoes to be seen—just spindly vines that had yet to yield fruit.
I couldn’t hide my disappointment. Clearly, whatever the successes van der Knaap had achieved in customizing fruit shape, an outsider like me wasn’t going to see them anytime soon. My visions of flawlessly symmetrical or outlandishly shaped fruit, daydreams born of those supermarket tangerines of my childhood, would continue to be unrealized, and the future of fruit shape remained a mystery.
Still, part of me wanted to believe that humans, after 10, 000 years of selecting and hybridizing weeds into commodity crops in pursuit of hardier, tastier, and prettier fruits and vegetables, may indeed be standing on a threshold.
I asked the professor what kind of DNA was trying to isolate in this room.
“A shape gene,” she said coyly.
Van der Knaap looked at me, paused, and smiled. “I’m not going to tell you.”