Study of microbial resistance and sensitivity for the development of effective food decontamination processes

Description

Despite the implementation of food safety control programs, there are more than 200 foodborne illnesses costing $35 billion/year in North America, with 4 million Canadians suffering from pathogen-related poisoning each year. With climate change, we must deal with microorganisms such as molds, which adapt to their new environment and become more resistant and more virulent. Cases of Salmonellosis are also increasing (8.8% for each degree of temperature increase) and are becoming increasingly common in Nordic countries.

Preservation techniques such as heat destroy pathogens but can affect the physicochemical, nutritional and sensory qualities of food and cannot be applied to fresh products. At the consumer’s request, the use of chemical additives must also be replaced by natural extracts that must be stabilized. Low-energy irradiation is a new emerging cold pasteurization technology that can be used on fresh and frozen packaged products without affecting the nutritional and functional qualities of the food. However, as with heating, some pathogens may be reduced to undetectable levels after irradiation but reappear during storage. These results suggest that bacteria have a stress adaptation system. On the other hand, the combination of treatments with cold pasteurization, by increasing microbial sensitization, allows reducing the time or dose required to ensure food safety. However, the increase in microbial sensitivity depends on the microbial genus and the food environment.

The mechanisms of microbial resistance and sensitization are still poorly understood. A better understanding of resistance mechanisms through the characterization of synthesized proteins and the identification of expressed genes will provide the information needed to understand the different resistance mechanisms in different microbial genera.
A better understanding of microbial resistance and sensitization mechanisms through treatments in combinations would allow the development of reliable technologies to ensure food safety without affecting the physicochemical and nutritional qualities of food. This will provide tools for decision-making in the control of foodborne infectious diseases and significantly reduce national health expenditures and increase the well-being of Canadians.

Objectives

To determine the influence of irradiation on the genomes of different microorganisms (sensitive vs. resistant to irradiation) to select genes whose expression varies.
Characterize and quantify radiation stress proteins in different microorganisms (sensitive vs. resistant to radiation).
Evaluate the effect of treatment combinations on microbial radiosensitization phenomena and assess the impact on overall food quality.

Beginning of the project

September 2025 or January 2026

Director

Monique Lacroix

Programme d’études

Master in Biology – Biotechnology or Ph.D. in Biology

Required Profile

Microbiology- Biochemistry – Food Science

Financial support

INRS offers financial support to its student community.

Lieu

Institut national de la recherche scientifique
Centre Armand-Frappier Santé Biotechnologie
531, boulevard des Prairies
Laval (Québec)  H7V 1B7
Canada

Questions

Monique Lacroix
Monique.lacroix@inrs.ca