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Application of the Impedance and Colorimetric Systems for Rapid and Cost Effective Detection of Listeria Species in Food and Environmental Samples


Listeria monocytogenes, the pathogenic species of Listeria has been shown to form biofilms in various food-processing surfaces. Biofilm growth of L. monocytogenes provides a substantial risk of pathogen contamination especially if wet surfaces are not maintained in a sanitary condition. Many food and meat processors test environmental swabs and sponges to confirm the absence of Listeria species, as part of their GMP and HACCP verification programs. Culture method, the most commonly used method, requires up to seven days to complete and does not fit well into these programs which require immediate remedial action.
This study will be assessing the application of two semi-automated systems, impedance-based system (Malthus) and a colorimetric-based system (Biosys) for rapid and low-cost detection of Listeria species, in food and environmental samples. The swab and sponge samples collected from a food processing plant which monitors for Listeria spp., specifically L. monocytogenes and L. innocua, the two most prevalent listerias in food processing environments will be tested.

More information

Expected Impact of Project Outcomes on Food Safety in Ontario: A validated Impedance and Colorimetric-based screening system for the detection of Listeria spp. in food and environmental samples which allows detection results within 24-30 hours of testing, as opposed to 6-7 days of testing by culture-based methods. This automated alternative reduces the cost of testing by 50%.
<P> For more information, please visit the <a href="; target="_blank">Ontario Ministry of Agriculture, Food & Rural Affairs (OMAFRA) Food Safety Research Program</a>.

Odumeru, Joseph
University of Guelph
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