Sophie Jan

Teacher researcher in microbiology

Department of Animal and Food Science

Teaching unit: Microbiology
Research unit: Science and technology of milk and eggs

Academic background

After a PhD thesis in the University of Picardie Jules Verne (UPJV ; Laboratoire de Génie Enzymatique et Cellulaire) and a year of post-doctoral studies at the STELA research center in Canada (University of  Laval, Canada ), I was assistant professor from 1996 to 2005 at the University of Maine. I then joined the Laboratory of Microbiology in the Department of Food in l'Institut Agro Rennes-Angers (UMR INRAE-L'Institut Agro Rennes-Angers).
My general theme of research relates to cellular engineering, for both prokaryotic and eukaryotic cells implemented throughout whole cell or at the macromolecular level.
In terms of academic research, my work focuses on the relationship between bacteria and their environment (symbiotic interactions between bacteria and plants; interactions between bacteria and food matrix) and the metabolism of fatty acids in eukaryotic cells (desaturases and lipases).
In terms of applied research, I work in a field relevant to food science: using whole cells or cell fractions for the production of molecules (polymer thickener, biodegradable plastic, lipid fractions enriched in polyunsaturated fatty acids) or for the increase in the value of raw materials (milk fat, egg white); and control of food hygiene.
I thus developed an expertise in cell culture (control of growing conditions, cell immobilization), analytical biochemistry (for the detection and quantification of cellular activity) and molecular biology (study of genes and their expression).
My research currently focuses on the microbiology of eggs and egg products and is organized into two major areas:
(i) Study of the anti-microbial activity of hen's egg white ,
(ii) Relationship between pathogenic/alteration bacteria and egg product matrices.


Industrial fermentations, metabolism of micro-organisms, general microbiology and hygiene of egg products (course and practice).

Research topics

My research is conducted in collaboration with Florence Baron, whose doctoral work initiated the research on microbiology of eggs and egg products in l'Institut Agro Rennes-Angers, under the direction of Michel Gautier.
Our research are organized into two topics :
The first topic concerns the study of anti-microbial activity of hens egg white. The egg white expresses a broad spectrum of bacteriostatic and bactericidal activities that we want to clarify. The results of this work should contribute to the understanding of the interactions between the matrix and micro-organisms and the basic mechanisms of micro-organism destruction. They should allow conceiving a better exploitation of the egg white anti-microbial properties.
The second topic concerns the control and improvement of egg products hygiene. We are studying the influence of technological processes and breading practices on the contamination of eggs and egg products in order to propose relevant ways of control at the product, the process or the upstream level.
Currently, our research focuses on bacteria belonging to the Bacillus cereus group since these spore-forming bacteria may be the cause of health and/or economic problems.
Indeed, some strains of this group produce toxins in food and/or in the intestine, which may induce emesis or diarrhoea, respectively. They also present a broad spectrum of enzymatic activities that may be responsible for egg product spoilage, even at low temperatures when psychrotrophic strains are involved.
We try to get new insights on the level of egg contamination, the species encountered, their ability to germinate, grow and produce toxins in egg products at different temperatures.
The aim is to get new insights on the risk associated with these bacteria in the sector of egg production and to consider relevant ways to control contamination. The control of this risk is a major competitive challenge for egg product manufacturers.


My publications on ResearchGate

My publications on HAL INRAE