Natural polymers developed to increase shelf life
By George Reynolds
8/23/2007 – New polymers and plastics developed could be used to satisfy growing demands for extended shelf life and products made from natural, sustainable sources, US researchers claim.
Scientists at Rutgers, State University of New Jersey, used antimicrobial agents derived from natural ingredients to create biodegradable polymers or plastics to block the formation of bacterial biofilms on the surface of foods and packaging.
Using natural sources such as cloves, oregano, thyme and paprika could provide processors with new ways of improving the safety and extending the shelf life of products. Moreover, consumers are increasingly appealed by products that are made from natural products, rather than those using synthetics. Moreover, the natural source potential allows the organic market to use these preservatives.
Biofilms are polymicrobial, which can harbor multiple versions of food-bourne illnesses causing bacteria, such as salmonella and E. coli.
Ashley Carbone, student at Rutgers constructed the polymer compounds used in tests by mating natural substances with controlled-release, biodegradable polymers that could inhibit or prevent bacterial biofilms.
Polymicrobial films are difficult to defeat using conventional techniques because each type of microbe present poses a unique challenge to the safety of food, said Kathryn Uhrich, the professor of chemistry and chemical biology advising Carbone.
“The natural substances we chose have general antimicrobial activities against many different kinds of microorganisms,” she said. “Therefore, the polymers into which we incorporated these natural substances have the potential to affect a much broader spectrum of microorganisms than organism-specific drugs.”
Furthermore, attacking the biofilm, rather than targeting specific bacteria, avoids the potential of the increasing antimicrobial resistance, which is an growing problem in the pharmaceutical industry.
In the presence or water or enzymes, the polymers biodegrade slowly as they release their active microbials. The benefit to the environment is that once a polymer has performed its job, it will breakdown naturally and not contribute to landfill.
“A slow and controlled release of the food-based antimicrobial would offer great advantages in the food industry, providing protection over an extended time and extending the shelf life of the food product,” Carbone said.
Michael Chikindas, associate professor of food science at Rutgers and co-investigator on the project, said that while consumers would benefit from safer food that lasts longer, by ingesting the polymers, they would not be adding to the antibiotic resistance.
Additionally, some antimicrobials carry some of the flavors and aromas of the sources from which they were derived, the researchers claim.
“The food people eat might even smell and taste better,” Chikindas said.