We've recently heard about a number of experimental antibacterial food-wrap films, that could replace conventional polyethylene. The latter does have some desirable qualities, though, so scientists have now developed a composite made from it.
Among other things, the polyethylene film that we're used to is strong, transparent, gas-permeable and water-resistant. It doesn't kill bacteria, though, which is where the new material comes in.
Created by a team at Pennsylvania State University, it incorporates a polysaccharide polymer known as pullulan, which is infused with a naturally-sourced antibacterial called Lauric arginate. Both pullulan and Lauric arginate are already approved for use in foods.
The researchers started by applying a coating of the mixture to one side of traditional polyethylene film. Getting it to stick required altering both the pullulan and the plastic, as polyethylene is normally quite hydrophobic (liquid-repelling).
Sheets of the resulting composite material (coated-side-in) were subsequently used to vacuum-pack pieces of raw beef, raw chicken breast and ready-to-eat turkey breast. All of the meat samples had been pre-inoculated with toxic E. coli, Salmonella spp., Listeria monocytogenes and Staphylococcus aureus bacteria. After the samples had been kept in refrigerated storage for up to 28 days, their bacterial populations were found to be significantly reduced.
"The novel composite film can give us antimicrobial properties and at the same time provide the strength and all the other desirable properties of polyethylene that the industry is still looking for," says the lead scientist, Prof. Catherine Cutter.
The research is described in a paper that was recently published in the International Journal of Food Microbiology.
Source: Penn State
