Paper-based packaging method to control Listeria and E. coli

The recent Listeria and E. coli O157:H7 outbreaks associated with cantaloupe and raw beef in North America reveal that the current available methods and procedures for food safety are failing to achieve full control of these deadly pathogens. New packaging approaches, by Canadian researchers from the Sentinel Bioactive Paper Network, for improving food safety are ongoing and can provide solutions for biocontrol by using immobilised phage.

To try to prevent these foodborne tragedies from happening in the future, researchers Hany Anany and Mansel Griffiths (University of Guelph) are using harmless viruses called phage to kill targeted pathogens (including Listeria and E. coli) that could be present on the surface of foods. A phage, in simple terms, is a harmless virus that can kill bacteria. Phage use has received regulatory FDA approval in the United States as a safe food additive in certain food products, along with Health Canada issuing a letter stating no objection for the use of phage. An immobilised phage can take over the Listeria and/or E. coli O157:H7 bacterial cell and produce new copies of itself inside the cell. After the phage reaches critical levels, the phage breaks open the bacterial cell and destroys it, thus not allowing the pathogen to multiply on a food surface (see below).

Sentinel researchers’ published work in the journal Applied and Environmental Microbiology describes their method to stick phage onto cellulose material and explains when foods (ready-to-eat meats, raw meats) are wrapped in the package, the harmful cells of Listeria and E. coli are killed by phage that have been placed on the packaging. This packaging option works at refrigeration temperatures, at which pathogens can still grow. The packaging solution can be used for modified atmosphere and vacuum packaged meats. This is one of several technologies being investigated by the Sentinel Network, a NSERC strategic network.

“This work has the potential to change the way today’s food packaging operates,” said Dr Mansel Griffiths, a Sentinel researcher and Director, Canadian Research Institute for Food Safety at the University of Guelph. “Through our research we also examined phage storage stability to further extend the use within industrial applications.”

Paper-based biosensors (bioactive paper) offer one of the best approaches for food safety monitoring because of their low-cost, simplicity and rapid response time. “Sentinel is working hard with its industry partners to bring phage-based anti-Listeria and E. coli materials to the marketplace. One vision is food packaging that inhibits Listeria and E. coli growth and warns the consumer or food supplier of contamination,” said Robert Pelton, Sentinel’s Scientific Director, McMaster University Professor and a Canada Research Chair.