Science

Composite food wrap kills bacteria

Composite food wrap kills bact...
Abdelrahim Hassan inspects a piece of the material
Abdelrahim Hassan inspects a piece of the material
View 2 Images
A piece of turkey, sealed within the film
1/2
A piece of turkey, sealed within the film
Abdelrahim Hassan inspects a piece of the material
2/2
Abdelrahim Hassan inspects a piece of the material

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).

A piece of turkey, sealed within the film
A piece of turkey, sealed within the film

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

2 comments
ChairmanLMAO
what ever happened to the tags that indicated whether food had been unrefridgerated for too long...that is probably the biggest hidden hazard of these foods. they should do the test in unrefridgerated environments. i have always been dumfounded to see packs of beef jerky sitting out on the counter and the pack reads does not need to be refridgerated...like yuk what the hale did they put in it so it wouldn't spoil?
VicCherikoff
Hey ChairmanLMAO.

Jerky is fine at ambient because the water activity (Aw) is so low. This is a measure of the availability of free water molecules in and around the jerky and a scale is used to set food safety standards for jerky and other dried meats that do not use chemical preservatives. Aw is also used for other food products and is packaging-related as it is a measure of the free water in the head space around the product.

Where it becomes a problem is in very humid environments where large bags of jerky are bought, opened and not resealed quickly or well. Then the dry meat can absorb enough moisture to raise the water activity past the point at which it is now able to support the growth of micro-organisms.

Some companies are using natural antimicrobials made from culinary herbs and spices (eg Herbal-Active) to add an extra level of food safety.