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Aurélien Maillet, currently Molecular Microbiologist Senior Scientist and phD student as part of a Cifre thesis with the company Mérieux-Nutrisciences on the project ALTEROBIO, brilliantly defended his thesis at Oniris on Tuesday, June 15, in front of the following committee:

Committee members:

• Florence Dubois-Brissonnet, Professor at AgroParisTech (UR INRAE Micalis)
• Christophe Chassard, Research Director at UMR INRAE research unit on cheese
• Graziella Midelet, Head of Unit (Bacteriology and Parasitology of Fishery and Aquaculture products Unit) at ANSES
• Olivier Firmesse, Researcher and leader of the Clostridium team within the Staphylococcus, Bacillus and Clostridium Unit (SBCL) of the ANSES Food Safety Laboratory

 Supervisors:

• Hervé Prévost, phD director
• Emmanuel Jaffrès, co-supervisor
• Sébastien Leuillet, co-supervisor

The subject focused on the study of the microbiota of the food factory environment and its impact on food quality and safety, and its application to the smoked salmon model.

Abstract of the PhD thesis:

Surface hygiene is an essential component of food industries quality system. Non-pathogenic bacteria are able to be resident in food processing factories and are generally unidentified but can be spoilers and contaminate foodstuffs at each processing step. Therefore, they might be a risk that must be controlled to ensure food safety and quality. In this study, cold-smoked salmon was used as a model to characterize the diversity of bacterial communities in food and food processing plants by 16S rDNA metabarcoding. A comparative analysis of different DNA extraction methods and surface sampling techniques has been performed to define their impacts on the results of a 16S metabarcoding analysis.     Therefore, it allowed us to select the study methodological conditions. Analysis of the diversity of bacterial communities in different batches of cold-smoked salmon showed a connection with the production facility in which they were processed. This suggests that the products bore a signature of the processing environment microbiota. Finally, a comparison of the products and processing environment surfaces bacterial communities allowed to identify the environmental sources of contamination. The use of this approach, in an industrial context, could lead to the implementation of targeted corrective measures in order to reduce product spoilage and the global food wastage.