Harvard and Rutgers scientists develop spray-on food coating to slash plastic waste

21 Jun 2022 --- University researchers have developed a biodegradable spray-on coating to protect foods against pathogenic and spoilage microorganisms and transportation damage. The new solution reduces plastic food packaging and associated waste.

The research was conducted by scientists at Harvard University, US, and funded by the Harvard-Nanyang Technological University with the Singapore Sustainable Nanotechnology Initiative.

Extended shelf life
In a journal article summarizing their research, Yi Wang, Jaya Borgatta and Jason C. White explain that this packaging technology uses polysaccharide/biopolymer-based fibers. The material is spun like a spider web from a heating device much like a hair dryer and then “shrink-wrapped” over solid foods, for example, an avocado or a sirloin steak. 

Innova Market Insights found that only 14% of consumers are optimistic about the future use of shrink wrapping, while more than 40% of consumers worldwide consider shelf life the most important factor in a purchase.

In line with this, the result of the newly-developed coating provides a durable and resistant outer layer that not only offers protection from bruising but also fights spoilage. Antimicrobial agents in the material prevent the growth of pathogenic microorganisms such as E.Coli and listeria, resulting in longer shelf life. We recently explored antimicrobial technologies in more detail.

The packaging material is spun like a spider web from a heating device like a hair dryer and then “shrink-wrapped” over solid foods.The research paper includes a description of the technology the wrap uses: a process called Focused Rotary Jet Spinning produces biopolymer. Quantitative assessments show that the coating extended the shelf life of avocados by 50%. Additionally, according to the study, the coating can be removed, rinsed off with water and incorporated with soil where it will degrade within three days.

Dr. Philip Demokritou of Rutgers University asserts that the research team “has come up with a scalable technology, which enables us to turn biopolymers, which can be derived as part of a circular economy from food waste, into smart fibers that can wrap food directly. This is part of a new generation of ‘smart’ and ‘green’ food packaging.” 

Demokritou is the director of the Nanoscience and Advanced Materials Research Center at the Rutgers School of Public Health and Environmental and Occupational Health Sciences Institute.

Possible solution to health risks
The rapid increase of petroleum-based plastic products in the waste stream is a serious environmental concern the development of this new packaging aims to target. Demokritou believes that efforts to limit the use of plastic, such as governmental intervention in states like New Jersey to eliminate plastic shopping bag distribution at grocery stores can help, but he wanted to do more.Tiny fragments of plastic are making it into the water we drink, the food we eat and the air we breathe.

“I’m not against plastics,” he explains. “I’m against petroleum-based plastics that we keep throwing out there because only a tiny portion of them can be recycled. Over the past 50 to 60 years, during the Age of Plastic, we’ve placed 6 billion metric tons of plastic waste into our environment. They are out there degrading slowly. And these tiny fragments are making it into the water we drink, the food we eat and the air we breathe.”

Evidence to support the potential health implications that excessive plastic waste could have is increasing with Demokritou’s research, while the paper describes how the new fibers function as a possible solution. 

They encapsulate the food and are laced with naturally occurring antimicrobial ingredients such as thyme oil, citric acid and nisin. The researchers can program these materials to function as sensors, where they then activate and destroy bacterial strains to ensure food will arrive untainted, which lowers the concern over food-borne illnesses, according to Demokritou. 

“We knew we needed to get rid of the petroleum-based food packaging that is out there and replace it with something more [environmentally] sustainable, biodegradable and nontoxic. We asked ourselves at the same time, ‘Can we design food packaging with a functionality to extend shelf life and reduce food waste while enhancing food safety?’” Demokritou believes this goal is achievable.

By Mieke Meintjes