Greening food preservation nurtures the environment

As consumers seek fewer preservatives in packaged foods — while the environment needs less plastic waste — Cornell scientists are finding ways to make active packaging materials with a bio-based polymer that helps salad dressings, marinades and beverages to last longer in the fridge.

The new research from Cornell will be published in June in the journal Food Packaging and Shelf Life.

“Active packaging gives us a new way to extend shelf life despite consumer demands for cleaner labels,” said food science doctoral student Ian Kay. “But it’s tricky. Foods and beverages have a variable and complex composition, so we need to know a lot about food chemistry and active packaging to determine which system works for which foods.

In the laboratory, a polymer of biological origin is grafted onto a plastic disc, to demonstrate how it can be used in food packaging.

Joshua Herskovitz, Ph.D. ’20, who studied in the lab of Julie Goddard, professor of food science in the College of Agriculture and Life Sciences, grafted the corn-derived polylactic acid polymer with l antioxidant nitrilotriacetic acid for use in food packaging. Kay, following on from Herskovitz’s work, discovered the material’s “interfacial pKa,” which tells you what pH the foods in that package might be operating at to avoid spoiling.

As the antioxidant is bound to polylactic acid, the preservative can interact with the food but not migrate into it.

“In other words, you get the shelf life of the preservative without consuming it,” Goddard said. “It allows for cleaner food, which is what consumers are really looking for these days.”

Active packaging technology using bioderived and biodegradable materials, such as polylactic acid, offers a way to reduce the two main contributors to municipal solid waste, Goddard said.

In 2018, the United States generated 68.13 million tons of food waste and 35.68 million tons of plastic waste, according to the Environmental Protection Agency. This combination of plastic and food accounted for 42% of all municipal solid waste going to landfill, contributing significantly to methane and carbon dioxide emissions.

“As a food scientist, I’m excited about new ways to reduce food and packaging waste,” Goddard said. “I’m not anti-preservatives as a whole, we have to remember that the things we use in the kitchen like heat, salt and lemon juice are important ingredients in preserving food.”

“So if we’re removing preservatives from our food, at the same time, we have to think about the environmental impact if the food spoils faster,” Goddard said. “By using a greener active packaging technique, we can extend shelf life while moving closer to a circular plastic economy.”

Goddard, a faculty member at the Cornell Atkinson Center for Sustainability, said this is an opportunity to show how this new preservation technology can work and address the larger environmental picture of reducing what goes to the landfill. “We want to reduce food waste,” she said, “and bring in bioderived materials to achieve that.”

The research, “The interfacial behavior of a polylactic acid-based active packaging film dictates its performance in complex food matrices,” was supported by the Department’s National Institute of Food and Agriculture American Agriculture.