Got Milk (Packaging)?

Edible food wrappers could reduce plastic waste and keep food fresher

SCHOOL CAFETERIAS have long been the setting for raucous debates over a very important question: How do you eat string cheese? The sticks of cheese wrapped in single servings have stirred hostility for years between the stringers and the biters. But in the near future, the conversation might have an entirely new focus: a wrapper you can bite right into and eat along with the cheese.

Researchers at the U.S. Department of Agriculture are developing packaging made from casein, a protein found in milk. The biodegradable film is not only edible—even nutritious, with the extra protein it would provide—but also able to protect food from spoiling longer than a standard plastic film by blocking oxygen roughly 250 times better. Plus, it could reduce plastic waste.

Research leader Peggy Tomasula, research scientist Laetitia Bonnaillie and their colleagues have been experimenting with types of casein, additives and processes to produce films for a variety of uses. When it arrives at their lab, casein is in powdered form. They add water and use a magnetic stirrer to mix it for two hours. They then add glycerol, an edible compound that makes the film more flexible. In some cases, they add citrus pectin, derived from citrus peels, to make the packaging stronger and more durable in humidity and higher temperatures. After vacuuming the bubbles out, they spread it on a silicone baking mat and let it dry in a chamber calibrated to a consistent temperature and humidity. Once the sheet is dry, they peel it off and let it sit for about a week.

In addition to wrapping single-serve cheese sticks, a more soluble version of the film could be used for instant coffee packets that dissolve in hot water (and make the coffee a bit creamier even before adding milk) or powdered soup packets, especially for “cream of ” soups. Individual portions would have to be packaged in larger containers to avoid contamination and contact with liquid, and any product using them would need to be marked for consumers with dairy allergies.

With the option to add flavoring right into the edible packaging, kids might soon be arguing over the best wrapper variety rather than the right way to eat the cheese.