SINGAPORE – Perishable foods such as fruits and meat are often at the mercy of harmful bacteria, especially when left outside the refrigerator for a long time.
To recover these foods, scientists have created a biodegradable packaging material that can kill harmful bacteria and fungi that grow on fresh produce.
The packaging also extends the shelf life of strawberries up to a week. Berries stored in ordinary boxes only stay fresh for four days.
The material – which looks like plastic – was created by researchers at Nanyang Technological University (NTU) and Harvard TH Chan School of Public Health in the United States.
The material is made from corn protein, starch and other naturally occurring substances, and is infused with a cocktail of natural antimicrobial compounds such as thyme oil and citric acid.
Laboratory experiments revealed that when the material detected increasing moisture levels and enzymes from harmful bacteria, its fibers released tiny amounts of antimicrobial compounds that killed bacteria.
The compounds can kill bacteria or fungi that thrive on both food and material. Dangerous microbes that thrive in food include E. coli and listeria, which cause one of the most serious forms of food poisoning.
The packaging is suitable for containing foods such as raw meat, fish, fruits, vegetables and ready-to-eat meals, said Professor Mary Chan, director of NTU’s Center for Antimicrobial Bioengineering who co-led the project.
She added that the team’s goal is to replace conventional plastic packaging with the new material which will also double the shelf life of the products.
“Vegetables are a source of waste because even if they are refrigerated, they will still breathe, causing spoilage after a week or two. With antimicrobial packaging, there is a chance to extend their shelf life … and also to make vegetables and fruits look fresh over time, ”she said.
Professor Chan noted that while there are already antimicrobial packaging on the market, the team’s material is considered the only one that is both biodegradable and capable of releasing bacteria-killing compounds only when needed. , such as when there is a rise in humidity.
This means that food will not be overly exposed to antimicrobial compounds.
The new material was made through a process called electrospinning – where corn protein, antimicrobial compounds with cellulose, and an acid are drawn into tubes using electrical force and made into fibers.
Harvard TH Chan School assistant professor Philip Demokritou, an expert in environmental health, noted that the new packaging would help manage the triple threats of food safety, food waste and unsustainable packaging.
The research team’s draft was published in October in the peer-reviewed journal ACS Applied Materials & Interfaces.
Packaging waste, including plastics, accounts for around a third of household waste in Singapore and is a key waste stream.
As part of the country’s efforts to reduce packaging waste, producers of packaged products and retailers, such as supermarkets with annual sales of over $ 10 million, will be required to submit data and develop plans to reduce, reuse or recycle their packaging materials by March 31 of next year.
The researchers hope to develop their technology with an industrial partner and commercialize their food packaging within two years.
They are currently working to refine and optimize the material’s manufacturing process and functionality. They are also studying other types of biopolymers – beyond corn proteins – to create different forms of sustainable packaging.
Professor Chan said their material will cost around 50% more than regular plastic packaging.
ComCrop – a local company that pioneered urban rooftop farming – had assessed the viability of the packaging material by scientists.
ComCrop Managing Director Peter Barber said: “As ComCrop seeks to develop its products to increase Singapore’s food production capacity, the volume of packaging we need will increase.
“The antimicrobial properties of the packaging could potentially extend the shelf life of our vegetables.”
He added that the new packaging must be cost effective.
“The first three things consumers in Singapore supermarkets will check are: price, price and price,” said Barber.