Département productions animales, agroalimentaire, nutrition (P3AN)
65, rue de Saint-Brieuc
F-35042 Rennes Cedex France
tel : +33 (0)2 23 48 58 61
fax : +33 (0)2 23 48 59 02
After a PhD thesis in the University of Picardie Jules Verne (UPJV ; Laboratoire de Gnie 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 AGROCAMPUS OUEST (UMR INRA-AGROCAMPUS OUEST 1253 Science et Technologie du lait et de l'Oeuf).
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).
My research is conducted in collaboration with Florence Baron, whose doctoral work initiated the research on microbiology of eggs and egg products in AGROCAMPUS OUEST, 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.
- Journal articles :
D'Andrea S., Guillou H., Jan S., Catheline D., Thibault J.N., Bouriel M., Rioux V. and Legrand P. 2002. The same rat delta6-desaturase not only acts on 18- but also on 24-carbon fatty acids in very-long-chain polyunsaturated fatty acid biosynthesis. Biochem. J. 264: 49-55.
Guillou H., Martin P., Jan S., D'Andrea S., Roulet A., Catheline D., Rioux V., Pineau T. and Legrand P. 2002. Comparative effect of fenofibrate on hepatic desaturases in wild-type and peroxisome proliferator-activated receptor alpha-deficient mice. Lipids. 37: 981-989.
Guillou H., Rioux V., Catheline D., Thibault J.N., Bouriel M., Jan S., D'Andrea S. and Legrand P. 2003. Conversion of hexadecanoic acid to hexadecenoic acid by rat delta6-desaturase. J. Lipid Res. 44: 450-454.
Rioux V., Daval S., Guillou H., Jan S. and Legrand P. 2003. Although it is rapidly metabolized in cultured rat hepatocytes, lauric acid is used for protein acylation. Reprod. Nutr. Dev. 43:.419-430.
Guillou H., D'Andrea S., Rioux V., Barnouin R., Dalaine S., Pedrono F., Jan S. and Legrand P. 2004. Distinct roles of endoplasmic reticulum cytochrome b5 and fused cytochrome b5-like domain for rat delta6-desaturase activity. J. Lipid Res. 45: 32-40.
Guillou H, D'andrea S, Rioux V, Jan S. and Legrand P. 2004. The surprising diversity of delta 6-desaturase substrates. Biochem. Soc. Trans. 32: 86-87.
Jan S., Guillou H., D'Andrea S., Daval S., Bouriel M., Rioux V. and Legrand P. 2004. Myristic acid increases delta6-desaturase activity in cultured rat hepatocytes. Reprod. Nutr. Dev. 44: 131-140.
Baron F., Cochet M.F., Ablain W., Grosset N., Madec M.N., Gonnet F., Jan S. and Gautier M. 2006. Rapid and cost-effective method for micro-organism enumeration based on miniaturization of the conventional plate-counting technique. Lait. 86 : 251-257.
Baron F., Cochet M.F., Grosset N., Madec M.N., Briandet R., Dessaigne S., Chevalier S., Gautier M. and Jan S. 2007. Isolement and characterization of a psychrotolerant and toxin producer Bacillus weihenstephanensis in liquid egg products.J. Food Prot. 70 (12) : 2782-2791.
- Thesis :
Jan S. 1991. Etude de l'immobilisation de Rhizobium meliloti pour la production d'exopolysaccharides. Mémoire de DEA, Spécialité Génie Enzymatique, Bioconversion et Microbiologie, Université de Picardie Jules Verne (UPJV)-Université de Technologie de Compiègne (UTC).
Jan S. 1995. Croissance et production de biopolymères par Rhizobium meliloti M5N1 : Effet de l'environnement. Thèse de Doctorat, Spécialité Génie Enzymatique, Bioconversion et Microbiologie, UPJV.
- Oral Communications :
Baron F.* and Jan S. Microbiologie de luf et des ovoproduits. Congrs de la branche Franaise de la WPSA, 23 mars 2006, Le Mans, France (confrence invite).
Baron F.* and Jan S. Egg and egg product microbiology : actual consideration on breeding and technological practices. Workshop of COST Action 923, 28-30 juin 2006, Turku, Finlande (confrence invite).
Jan S.*, Baron F. and Gautier M. Growth and cytotoxic activity of Bacillus weihenstephanensis in liquid egg products at low temperatures. B. cereus meeting, 2122 mai 2007, Guyancourt, France (confrence invite).
Jan S.*, Cochet M.F., Grosset N., Madec M.N., Briandet R., Dessaigne S., Chevalier S., Gautier M. and Baron F. Isolation of a spore-forming, psychrotolerant Bacillus weihenstephanensis in liquid egg products stored at low temperatures : study of growth, cytotoxicity, and ability to stick and form biofilms. II International Conference on Environmental, Industrial and Applied Microbiology (BioMicroWorld2007), 28 novembre-1 dcembre 2007, Séville, Espagne.