Researchers develop coated paper to preserve packaged food

Paper that holds products together while killing bacteria that cause spoilage been developed by Bar Ilan University institute scientists.

By JUDY SIEGEL-ITZKOVICH
A special paper that, when used as food packaging, holds products together while killing bacteria that cause spoilage has been developed by scientists at Bar-Ilan University’s Institute of Nanotechnology and Advanced Materials.
Dubbed “killer paper,” the product is coated with silver nanoparticles and has been proven successful in lab tests.
The invention was recently described in an article titled “Sonochemical Coating of Paper by Microbiocidal Silver Nanoparticles” in the American Chemical Society journal Langmuir.
The team was headed by Prof. Aharon Gedanken, director of Bar-Ilan’s Kanbar Laboratory of Nanomaterials.
He and colleagues noted that silver already finds wide use as a bacteria-fighter in certain medicinal ointments, kitchen and bathroom surfaces, and even Israeli-developed odor-resistant socks.
Recently, BIU scientists have been exploring the use of silver nanoparticles – each 1/50,000 the width of a human hair – as germ-fighting coatings for plastics, fabrics and metals. Nanoparticles, which have a longerlasting effect than larger silver particles, could help overcome the growing problem of antibiotic resistance, in which bacteria develop the ability to shrug off existing antibiotics.
The scientists suggested that paper coated with silver nanoparticles could provide an alternative to common food preservation methods such as radiation, heat treatment and low temperature storage. But producing “killer paper” suitable for commercial use has proven difficult.
The team described development of an effective, long-lasting method for depositing silver nanoparticles on the surface of paper, involving ultrasound, or high-frequency sound waves. The coated paper showed potent antibacterial activity against E. coli and S. aureus, two causes of bacterial food poisoning.
This killed all of the bacteria in just three hours, and suggests its potential application as a food packaging material for promoting longer shelf life, the team wrote.