A study by researchers at Rensselaer Polytechnic Institute used enzymes attached to food-safe silica nanoparticles to create a coating that kills listeria.

The method aims at an alternative to chemical or antibiotic decontamination of various foods during handling and packaging.

The findings were published in April in Scientific Reports.

The coating killed listeria within a few minutes of contact without affecting other bacteria.

The cell lytic enzymes can also be attached to starch nanoparticles used in food packaging, according to the researchers. On meat, for example, edible starch is often sprayed into packaging as a powder layer.

“Stable enzyme-based coatings or sprays could be used in food supply infrastructure — from picking equipment to packaging to preparation — to kill listeria before anyone has a chance to get sick from it,” Rensselaer Polytechnic chemical and biological engineering professor Ravi Kane said in a news release. “We can adapt this technology for all different kinds of harmful or deadly bacteria.”

Kane co-authored the study with Jonathan Dordick, vice president of research; Linda Schadler, professor and associate dean at the Rensselaer School of Engineering; and several postdoctoral and graduate researchers.

To stabilize the enzymes, the researchers attached them to silica nanoparticles to create an ultra-thin film. For the edible starch nanoparticles, they used maltose binding protein.

At higher concentrations up to 100,000 bacteria per milliliter — exceeding typical contamination incidents — both techniques killed listeria within 24 hours.

Ongoing research will look at using lytic enzymes to target various bacteria.

In 2010, Rensselaer researchers created a coating to kill methicillin-resistant staphylococcus aureus, a bacteria responsible for antibiotic-resistant infections. It was developed for use on surgical equipment and hospital walls.