A team of scientists from the NTU Singapore y the Harvard TH Chan School of Public Health, USA, have developed a “smart” food packaging material that is biodegradable, sustainable and kills microbes that are harmful to humans. It could also extend the shelf life of fresh fruit by two to three days.

Natural food packaging is made from a type of corn protein called zein, starch, and other naturally-occurring biopolymers, infused with a cocktail of natural antimicrobial compounds (see video). These include thyme oil, a common herb used in cooking, and citric acid, which is commonly found in citrus fruits.

In laboratory experiments, when exposed to increased moisture or harmful bacteria enzymes, the fibers in the packaging have been shown to release natural antimicrobial compounds, killing common dangerous bacteria that contaminate food, such as E. coli and Listeria, as well as mushrooms.

The container is designed to release the necessary minute amounts of antimicrobial compounds only in response to the presence of additional moisture or bacteria. This ensures that the packaging can withstand multiple exposures and last for months.

As the compounds fight any bacteria that grow on the surface of the package, as well as in the food product itself, it has the potential to be used for a wide variety of products, including ready-to-eat foods, raw meat, fruits, and vegetables.

In one experiment, strawberries that were wrapped in packaging stayed fresh for seven days before developing mold, compared to counterparts that were kept in conventional plastic fruit boxes, which only stayed fresh for four days.

The invention is the result of the collaboration of scientists from the NTU-Harvard TH Chan School of Public Health Initiative for Sustainable Nanotechnology (NTU-Harvard SusNano) , which brings together researchers from NTU and Harvard Chan School to work on cutting-edge applications in agriculture and food, with an emphasis on developing non-toxic and environmentally safe nanomaterials.

The development of this advanced food packaging material is part of the University's efforts to promote sustainable food technology solutions, which is aligned with the strategic plan NTU 2025 , which aims to develop sustainable solutions to address some of humanity's great pressing challenges.