SF6027 - Rapid Phage-Based Method for the Detection of Pathogens in Food

Researcher:

Dr. Mansel Griffiths, Dept. of Food Science, University of Guelph

Objectives:

• To develop and evaluate a bacteriophage-based capture and detection system for food-borne pathogens in food and environmental samples.

Expected Benefits:

• The test developed from this project will enable processors and regulatory agencies to quickly establish whether a specific pathogen is present in food and provide an estimate of the level of contamination.

Summary of Research Results:

A method capable of detecting specific microorganisms present in low numbers in food within a meaningful time-frame still remains the holy grail of food microbiologists. Present methods are either i) too long, ii) too laborious, iii) too costly, iv) lack specificity or v) lack sensitivity. The objective of this research was to develop assays that can provide rapid, reliable results in a time that has practical significance for the food industry. We are using bacteriophage (viruses that only infect bacteria) as agents to carry genes whose products can easily be detected into target bacteria. These methods make use of the innate specificity of bacteriophage towards their host. The use of bacteriophage also provides for a natural amplification of the detection signal due to the replication of the phage in the host cells. This process only takes 1 to 2 hours. We have shown that it is possible to immobilize bacteriophage on surfaces and to use them to capture harmful bacteria from a food sample. Following replication inside the host cell, the phage can then be detected using a variety of simple assays. We have also shown that it is possible to "label" the phage, so that, when it replicates in the host cell it emits light that can be measured using simple instruments called luminometers.