Edible Films With Superpowers

New Brunswick, N.J.

Skip to next paragraphPhotographs by Peter DaSilva for The New York Times

ANTIMICROBIAL Tara McHugh, above, works with films made from puréed vegetables at the Western Regional Research Center in Albany, Calif.

LEAVE heirloom tomatoes to the organic farmers and pork belly to the chefs. In the chemistry department at Rutgers University and other laboratories like it, the real action is in less trendy ingredients like oregano, crab shells and milk.

In a handful of food science labs around the country, people who talk about food in terms of microbes and polymers have been turning the natural pathogen fighters found in everyday food into edible films and powders.

If their work pans out, thin films woven with a thyme derivative that can kill E. coli could line bags of fresh spinach. The same material in powder form might be sprinkled on packages of chicken to stop salmonella.

Strawberries could be dipped in a soup made from egg proteins and shrimp shells. The resulting film — invisible, edible and, ideally, flavorless — would fight mold, kill pathogens and keep the fruit ripe longer.

For average eaters who are still scratching their heads over trans fat, food coated with invisible films that lure bad microorganisms to their death might as well be nuclear fusion. But food scientists believe the potential for using these everyday ingredients to make a safer food supply is huge.

“These natural films are really a very hot topic these days,” said Michael Chikindas, a food scientist working with the team at Rutgers. “The range of applications is endless, from very delicate foods to Army rations and space missions.”

On the most basic level, the films are something like a plastic wrap made of edible components that dissolves in water. The films can be infused with molecules from cloves, thyme or other foods that can keep unhealthy bacteria from growing. They can even be manipulated to carry flavor.

Of course, what works in the lab doesn’t always translate to the production line. As far as most of the scientists know, these new edible antimicrobial films and powders have yet to coat any food on the market. But their time is near, researchers say. Patents are pending and several large companies, commodity groups and the federal government have invested money in the research.

In any food processing innovation, the timing has to be right for both consumers and manufacturers, and this might be the moment. Reports of food-borne sickness outbreaks have become part of the daily news. Just last week, baby carrots infected with shigella, a bacteria, were recalled in 12 states. In July, 86 brands of canned chili sauce and other meat products were recalled in a botulism scare. In June consumers were advised to throw away bags of the snack called Veggie Booty after salmonella in it made people in 17 states sick.

As shoppers demand safer food, they’re also demanding healthier food made with ingredients they can pronounce.

“We’re working on consumer-friendly antimicrobials, so people will read the package label and not freak out,” said Mark Daeschel, a professor of food science at Oregon State University.

Professor Daeschel teamed up with the food scientist Yanyun Zhao to engineer an edible film made from a fiber found in crab and shrimp shells. They mixed in lysozyme, a protein found in both eggs and human tears that has proven effective against listeria and staphylococcus. “It’s why we don’t get eye infections,” he said.

The result is a film that could coat fruit or meat or even become an edible yogurt lid.

Beyond concerns for safer food and more natural products, the researchers are enjoying another bit of good timing: Consumers are becoming accustomed to thinking about edible film as a product that can deliver mouthwash and cough syrup. Why not food?

“One of the big breakthroughs were those Listerine strips,” said Tara McHugh, a food researcher with the Department of Agriculture who makes films from carrots and tomatoes. “Consumers have just become more comfortable eating films.”

Many people already eat more films and coatings than they realize. The wax on apples and the coating on aspirin are examples of edible protective layers used to battle oxygen, moisture and mishandling.

Most coatings are made from gluten, cellulose, starch and various proteins approved by the Food and Drug Administration as safe for consumption. They line ice cream cones and coat battered frozen food. A layer of film in some frozen pizzas keeps moisture from the sauce from seeping into the crust. Fresh sliced apples and other produce get coatings of ascorbic acid to keep them from turning brown.

Indeed, many shiny confections like chocolate-covered almonds and raisins are coated with confectioner’s glaze, a substance that might make some snackers cringe. It is often made with the secretions of a mite-sized beetle that lives in India and Thailand.

Making confectioner’s glaze also requires ethanol, which is regulated by the Environmental Protection Agency, said Dr. John Krochta, a food scientist at the University of California at Davis. The new kinds of edible coatings might eliminate the need for ethanol, he said.

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