Gaetan Podeur Email & Phone Number

Rennes Area, France

Maisons-Alfort

Paris Area, France

Nantes Area, France

Project : Quantification of histamine-producing bacteria and control of histamine formation in seafood by biopreservationHistamine-producing bacteria were isolated from naturally contaminated seafood, some of responsible for histamine-poisoning. At the same time, lactic acid bacteria were isolated on the same products and clustered according to their inhibitory activity against 4 histamine-producing species. Most of the strains were identified as Lactobacillus fuchuensis or Lactobacillus sakei. Twelve lactic acid bacteria were selected for challenge-test on canned, cooked or smoked tuna. Challenge-test combined with sensory analysis performed on cooked vacuum-packed tuna against Morganella psychrotolerans and Morganella morganii, demonstrated an important inhibitory effect on growth and production of histamine with L. sakei CNCM I-4707. Bacterial count was reduced by 3 to 5 log CFU/g and histamine production was reduced under 50 mg/kg by L. sakei after 4 days of storage at 15°C and 11 days at 4°C (for M. psychrotolerans). Based on sensory evaluation, biopreservation performed with L. sakei also extended the shelf-life of cooked tuna up to 8 days at 15°C. A real-time PCR method specific of M. psychrotolerans and M. morganii with a selective enrichment step was developed. After enrichment, this method allowed to quantify M. psychrotolerans and M. morganii between 50 CFU/g to 104 CFU/g, while direct amplification quantified these bacteria between 104 CFU/g to 109 CFU/g. Finally, the development of a new RT-qPCR method was initiated to demonstrate an over-expression of the genes involved in the reduction of histidine into histamine under acidic stress.Keywords: biopreservation, tuna, lactic acid bacteria, scombroid poisoning, Morganella morganii, Morganella psychrotolerans, Lactobacillus sakei, sensory analysis, real-time PCR, enrichment step, RT-qPCR

Roquefort-Sur-Soulzon (Aveyron)

Project : Quantification of Penicillium roqueforti in Roquefort cheese and resarch of correlation between growth and fonction. This project was divided into 4 missions :_ Transfer of a new qPCR method to quantify P. roqueforti mycelium during the different steps of Roquefort production_ Growth study of P. roqueforti during ripening and after packaging by molecular, classical microbiology methods and microscope observation_ Comparison of the effect of two different strains of P. roqueforti on cheese ripeningFinally, this work provides news informations on P. roqueforti and its function during ripening which will help to improve overall quality of Roquefort cheese for consumers.

Research Doctorate, Food Microbiology, Phd

Activities and Societies: Ressearch in fish industry in collaboration with Ifremer and Oniris PhD

Master'S Degree, Microbiology, General

Licence, Health And Biology

Dut, Biochemical And Microbiological Analyses

Education record

Education record