A Smarter Shelf Life
by Eve Daniels
Most of us have been there: Standing with the refrigerator door open, holding a carton of milk in our hand, glancing at the expiration date, smelling it to make sure.
Although this common safety check might seem sufficient, it’s actually more of a wild guess. Expiration dates are based on how long it takes for bacteria to grow, but they aren’t necessarily accurate. There are a lot of variables that come into play.
“Something can happen during the food fabrication or transportation and the food can spoil before that date,” says Abdennour Abbas, assistant professor in the Department of Bioproducts and Biosystems Engineering. “It can also still be good, but people throw it out anyway.”
In other words, labels like “use by” or “best before” aren’t much more reliable than our noses.
When Abbas joined the University of Minnesota faculty in 2013, he had already expressed an interest in investigating this problem. But he didn’t realize the urgency of the problem until February 2014, after reading a report on food losses by the USDA.
According to that report, 31 percent — or 133 billion pounds — of the 430 billion pounds of the available U.S. food supply went uneaten in 2010. The estimated value of this loss? More than $160 billion per year.
Stunned by these figures, Abbas was compelled to share them with his University of Minnesota colleague, Marin Bozic, an applied economist who specializes in dairy foods marketing research.
“Marin couldn’t believe it either,” says Abbas. “He said, ‘Are you sure that’s not millions instead of billions?’” The two researchers decided to join forces — drawing on Abbas’ technical expertise and Bozic’s industry knowledge — to bring a viable solution to market.
Their MnDRIVE-funded project, “Bioresponsive Food Packaging for Continuous Monitoring of Food Spoilage,” incorporates a label that changes color when food has gone bad. Other collaborators on the project include Francisco Diez-Gonzalez, head of the Department of Food Science and Nutrition, and undergraduate student John Brockgreitens.
“It’s a sensor, like a sticker, that we put in contact with the milk, but it can be seen from the outside through a transparent window,” Abbas explains. “It can be applied not only to dairy products but also to meat and other foods, to anything with plastic or paper packaging.”
The bioresponsive label goes from blue to red when it comes in contact with changing pH levels, indicating deterioration in real time. It’s made with a polymer that shares some of the same lipids we find in milk. So, even if it gets in the food, it’s safe.
While a number of other scientists have developed a similar technology, they’ve failed in commercializing it, says Abbas. “The biggest challenge is how to get this into the fabrication process in an easy and cost-effective way.” Specifically, the goal is to implement the label at a cost of 1 cent per package or less.
The prospects look good. In November, Abbas and Bozic visited the Tetra Pak plant in Vancouver, Washington, to learn about their fabrication process and how their label could fit into that process. The multinational company provides environmentally sound food packaging products to hundreds of millions of people in more than 170 countries.
“Thanks to that visit, the company is interested in exploring biosensors,” says Abbas. “We’re hoping to make prototypes soon for them to study the feasibility.”
“We think this technology could be a game changer, but now we need to convince dairy processors and packaging manufacturers that this is also in their best interest,” adds Bozic. “We believe if we can get the technology to be cheap enough so that consumers are willing to pay for the additional costs, this could be a win-win solution.”