Harvard researchers develop antimicrobial food packaging in biodegradability boost

07 Jan 2022 --- Researchers at Harvard T.H. Chan School of Public Health, US, and Nanyang Technological University, Singapore (NTU) are developing a “smart” food packaging material that is biodegradable and kills harmful microbes. 

The packaging material – which is made from a type of corn protein called zein, starch and other naturally derived biopolymers, infused with a cocktail of natural antimicrobial compounds – could also extend the shelf life of fresh fruit by two to three days, say the study authors.

Meanwhile, the COVID-19 pandemic has heightened consumer hygiene concerns, giving rise to touch-free packaging designs and antimicrobial technologies. According to Innova Market Insights, 59% of global consumers believe packaging’s protective function is more important since the virus outbreak.

Killing harmful bacteria
A lab experiment conducted by the researchers showed that when exposed to an increase in humidity or enzymes from harmful bacteria, the fibers in the packaging release the natural antimicrobial compounds, killing common dangerous bacteria that contaminate food, such as Escherichia coli (E. Coli), Listeria and fungi.

The scientists explain the packaging is designed to release the antimicrobial compounds when confronted with additional humidity or bacteria.

The natural food packaging is suitable for ready-to-eat foods, raw meat, fruits and vegetables. “This [design] ensures that the packaging can endure several exposures, and last for months,” they add.

Reducing petrochemical plastics
As the natural food packaging can be used for various products, such as ready-to-eat foods, raw meat, fruits and vegetables, there is potential for the product to be used on a large scale.

Director of NTU’s Centre of Antimicrobial Bioengineering and co-leader of the project, professor Mary Chan, says: “This invention would serve as a better option for packaging in the food industry, as it has demonstrated superior antimicrobial qualities in combating a myriad of food-related bacteria and fungi that could be harmful to humans.”

“It could serve as an environmentally friendly alternative to petroleum-based polymers used in commercial food packaging, such as plastic, which have a significant negative environmental impact,” she adds. 

Philip Demokritou, adjunct professor of environmental health at Harvard Chan School and director of the Nanotechnology and Nanotoxicology Center and co-director of NTU-Harvard Initiative on Sustainable Nanotechnology, stresses the positive effects of working with nature-based compounds.

“In this study, we used nature-derived compounds to synthesize smart antimicrobial materials which can be used not only to enhance food safety and quality but also to eliminate the harm to the environment and health and reduce the use of non-biodegradable plastics at global level and promote sustainable agri-food systems.” 

Extended shelf life
An experiment by the university researchers revealed that strawberries stay fresh for seven days before turning moldy using the biodegradable material, compared to four days for strawberries packaged in typical fruit plastic boxes. 

Even so, research by Innova Market Insights indicates 60% of global consumers are willing to compromise shelf life to reduce plastic packaging.An experiment demonstrated strawberries stay fresh for three days longer using the new material. 

However, the market researcher also found more than half (64%) of global consumers agree with the statement that making a product more environmentally sustainable should not reduce the packaging performance. 

Relatedly, scientists at Swiss Federal Laboratories For Materials Science and Technology and Lidl Switzerland recently developed an ecological nanofiber film for bananas to avoid plastic packaging and ensure longer shelf life.

Also, Sufresca, an Israeli agritech start-up, has developed an edible fruit and vegetable coating, slowing down fresh produce’s ripening process and replacing conventional single-use plastic packaging. 

By Natalie Schwertheim