The Bright, Hi-Tech Future of Food Preservation

Irradiating food? Pssh. Old news. Engineers are working on more effective (and cooler) techniques like super-high pressure, chemical coatings, and, yes, laser ovens.

By David H. Freedman|Friday, September 2, 2011
illustration by David Plunkert

The average American kitchen is lousy with innovation. Science has bombarded us with convection microwave ovens, induction cooktops, and countless other curiosities aimed at making food preparation tidier and more efficient. Yet for all the patents crowding our counters, every time I put together a meal I find myself facing some tediously antique trade-offs: Would I prefer wholesome, quick, or safe? Maybe I can figure out how to achieve two, or even 
all three? Haven’t cracked that one yet.

The truth is that nutritious, delicious food is quite difficult to obtain quickly. “Quickly” has traditionally meant either cooking food beyond recognition (safe but disgusting) or barely cooking it at all (also disgusting, if you ask me). Raw or rare food may be popular among health nuts, but it is also an attractive dining option among the world’s largest constituency, bacteria, a population riding high on its recent success in contaminating produce in Germany and killing 48 people as of July. Foodborne diseases in this country aren’t much friendlier, striking one-sixth of the entire U.S. population every year, according to the Centers for Disease Control and Prevention.

The clear way around the problem is to kill bacteria through means other than heat prior to preparation, so you can then cook food or not, to your liking, without having to worry about contamination. “The goal is to apply a lethal agent that causes a minimum of change to the nutrients and other ingredients,” says V. M. Balasubramaniam, a food engineer at Ohio State University. Chemical preservatives raise health concerns of their own, and at any rate they are not applicable to many foods. Blasting food with beams of high-energy electrons, X-rays, or gamma rays also fits the bill, but the CDC reports that at least half of all Americans say they will not eat irradiated foods if given a choice. As a result food-zapping techniques in the United States are limited to just a few fruits and spices.

Balasubramaniam is studying a different line of attack, subjecting flora and butchered fauna to 100,000 pounds per square inch of pressure (PDF), some 6,000 times the atmospheric pressure at sea level.

No ordinary pressure cooker can achieve such compression. Balasubramaniam employs a special type of pressure chamber that was originally designed to make industrial diamonds. He starts by sealing food in a plastic bag and dropping it into an upper compartment filled with water. A piston separates this compartment from a lower one that’s filled with hydraulic oil. More hydraulic fluid is pumped into the lower compartment, which raises the piston and in turn compresses the water—only a little, though, because water is highly resistant to compression. As the water becomes slightly more squashed over a two-minute period, the pressure in the upper compartment skyrockets. After five minutes the pressure is released. Dinner is served.

Something really surprising happens to many foods when subjected to this sort of megapressure: nothing. The compression induces no chemical changes and therefore causes no odd tastes, textures, or appearances. Raw meat takes on a brownish tinge, owing to some misshapen proteins, but solid, liquid, or gooey foods (such as potatoes, pineapple, and tomato sauce) or foods that are sliced flat (like a serving of ham or salmon) are generally none the worse for wear. Bacteria stay perfectly intact too—except that they are quite dead, because the pressure contorts their DNA and proteins into nonfunctional shapes.

The result is food that is perfectly safe to eat, even raw. “I take raw hamburger, compress it, and then cook it just a little bit on the grill to make it look better on the outside,” says Antonio Torres, a food scientist at Oregon State University who also works with food compression. “It’s rare and juicy and delicious, the way a hamburger should be. Everyone I serve it to loves it. I’m taking some home tonight.”

That’s right, a perfect, rare burger without the bacteria. Try getting that at Burger King or wherever it is you take your spouse on your anniversary.

The benefits of high-pressure technology are not limited to burgers. Eggs lose their sulfurous odor, returning dignity to the otherwise delightful egg salad sandwich. Oysters, shrimp, and lobsters cleanly separate from their shells and emerge appealingly firm due to pressure-induced protein coagulation. That means raw lobster, normally slimy and inedible, becomes a whole new safe and tasty treat. “I’d like to try this,” says the not-easily-impressed Hervé Malivert, chef-coordinator at the International Culinary Center in New York.

Hey, get in line. And start saving: A compression machine like the one Balasubramaniam uses sells for about $3 million. For that reason, the technology has been adopted only by large industrial food processors, like Oscar Mayer and Hormel, and applied to foods for which some consumers are willing to pay a price premium of 5 to 10 percent to cover the extra processing cost. Right now, a couple of brands of deli meat and packaged guacamole are the only compression-treated foods you’re likely to run into at your local supermarket. These items justify the special treatment because they can be slapped with the “preservative free” label that makes some chemophobic shoppers happily willing to shell out an extra 50 cents. Balasubramaniam predicts companies could begin selling smaller, cheaper models for the home within a decade. “There’s a real advantage to point-of-consumption compression,” Balasubramaniam says, noting that a home compressor would mean you could buy raw, unpreserved food, throw it in the machine for a few minutes, and either heat it or eat it raw without fear. Sushi would be a natural for this treatment; Balasubramaniam says he’s working with fish and has obtained good results.

Crushing lettuce with 100,000 psi is another matter. Leafy greens and strawberries get mashed to almost nothing. This is no small disadvantage, since raw fruits and veggies are especially vulnerable to spoilage and contamination with E. coli and other harmful bacteria, as we are painfully reminded whenever tomatoes, spinach, cucumbers, and other greenery shows up in the news as killers. To make matters worse, washing fruit to rid it of surface contaminants tends to accelerate rotting, because it removes the plants’ natural waxlike protective barrier, sometimes called the “bloom” or the “cuticle.”

An ingenious solution to this knotty problem comes from Yanyun Zhao, another food scientist from Oregon State. Zhao uses a mixture of chitosan, a cellulose-like compound extracted from crab shells, and lysozyme, an enzyme taken from egg whites, to create a liquid that can be applied and dried to form an edible, antibacterial coating on berries and other produce. One dip in the liquid can double the food’s shelf life, Zhao reports. She is working to commercialize the dip, although first she must resolve a couple of problems. One, the dip would render produce flora non grata to anyone with a shellfish or egg allergy. The other problem—less lethal, but possibly commercially deadly—is that the coating, though edible, is not entirely tasteless. “In tests, consumers say it tastes, uh, pretty good,” Zhao says, a little unenthusiastically.

As scrumptious as crab-fortified raspberries sound, the food-prep technology that I am most excited about is the multilaser oven, invented, sort of, by Ludovic Peperstraete at the International School of Design in Valenciennes, France. A few years ago Peperstraete stumbled on an article in a science journal about medical researchers using crossed laser beams to image and heat tumors in a patient without disturbing any of the surrounding tissue. “I realized this was a way to make the perfect moelleux au chocolat,” Peperstraete says, referring to the classic French dessert comprising a warm cake with a liquid chocolate filling. Mounted in an oven, the crossed beams could melt the chocolate interior with pinpoint accuracy, even as they monitor the corresponding change in texture and trigger the heat to shut off at just the right moment. The same technique could produce the perfect medium-rare turkey burger—cooked, not compressed.

At least it works on paper. Peperstraete’s idea is still a concept. Building an actual laser oven will take some time. “I think we’ll have this in our kitchens in about 100 years,” he says with (one infers) a bone-dry French wit.

That’s well within my projected life span, I reckon, if I continue my healthy eating. And if by some freak turn of bad luck I kick the bucket before then, at least I know there is a means for preserving my remains bacteria-free until science figures out how to reverse the compression process and restore me. Who knows what advances they will have made in deli meat by then.

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