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• Un symposium était organisé par Nabila Haddad, enseignant-chercheur à Secalim avec trois communications associées dont celle de Benjamin Duqué, doctorant à Secalim

Challenges in Campylobacter Detection and Control

Campylobacteriosis is the most frequently reported zoonosis worldwide . Control of Campylobacter along the food chain is troublesome and there is a clear relationship between the prevalence of Campylobacter in broiler flocks and public health risk. Chickens serve as reservoirs, and Campylobacter’s ability to survive on chicken fillet depends on its ability to survive the scalding (i.e., heating step), chilling and subsequent storage steps. Strain vari-ability and cell history affect the robustness of Campylobacter along the chain and quantitative knowledge is needed to refine microbiological exposure assessment models and to evaluate the impact of industrial control interventions. The effectiveness of control measures is verified by microbiological testing. Testing efficacy is however hampered by the fact that Campylobacter is often damaged in food and may only represent a small fraction of the total microflora in food. Analytical testing methods, therefore, incorporate an enrichment procedure to recover and selectively amplify Campylobacter to higher concentrations allowing subsequent detection . These enrichment-based detection methods are in practice not perfectly selective and sensitive . This symposium focuses on the challenges to control and detect Campylobacter along the food chain . It will highlight the advances to predict the robust-ness of Campylobacter to survive along the food chain using molecular markers taking into account cell history and strain variability . It will also discuss the effects of strain variability and competitive flora on the outcome of enrichment-based detection procedures, and it will give an update about the lessons learned and the difference between qualitative and quantitative standards to control Campylobacter in products .

• • Challenges of Campylobacter Detection - Effect of Strain Variability and Competitive Flora on Enrichment-based Detection Procedures

HEIDY DEN BESTEN, Wageningen University,  Wageningen, The Netherlands

Survival of Campylobacter in the Food Chain; Robust-ness of Model Prediction Using Molecular Markers BENJAMIN DUQUÉ, UMR1014 Secalim, INRA,  Oniris, Nantes, France

• • Efficacy and control measures - Lessons learned and regulatory Aspects

MICKAEL WILLIAMS U.S. Department of Agriculture – FSIS, Washington, D.C., US

• Une communication orale était également présentée par Aurélien Maillet, doctorant à Secalim

Impact of Residential Bacteria on Product Quality:The Cold-smoked Salmon Case AURELIEN MAILLET, Agnès Bouju-Albert, Steven Roblin, Pauline Vaissié, Sébastien Leuillet, Xavier Dousset, Emmanuel Jaffrès, Jerome Combrisson, Hervé Prévost. UMR 1014 SECALIM, UBL, INRA, Oniris, Nantes, France

Introduction: In  the  food  processing  environment,  bacteria  are  able  to  remain  on  surfaces  after  sanitization  procedures .  These  surface  residential  bacteria are a major source of product contamination and spoilage and play an essential role in food safety and quality . In order to manage food safety in the food processing plant, surface residential bacterial community characterization is an important concern . Purpose: This study aimed to characterize the bacterial communities of the processing environment and to evaluate the impact on cold-smoked salmon (CSS) quality. A polyphasic approach based on culture-dependent method, 16S metabarcoding, chemical and sensory analysis was used. Methods: Samples from surfaces of a CSS processing plant and from products during the process and storage all along the shelf life were collected . Bac-teria were plate counted and identified by MALDI-TOF MS or full 16S rDNA sequencing. DNA was extracted directly from samples and analyzed by V3-V4 16S metabarcoding . Chemical and sensory analyses were performed on end-products . Results: The residential bacterial surface community was identified and characterized as homogeneously spread within the processing plant. This “house microbiota”  was  mainly  composed  of  spoilage  bacteria  such  as  Brochothrix  thermosphacta,  Carnobacterium  maltaromaticum,  Serratia  liquefaciens,  Psychro-bacter spp ., and Pseudomonas spp . Beta-diversity and network analysis allowed to highlight environmental bacterial source hotspots and to identify contam-ination routes . These results were consistent with the sensory analysis . Significance: Microbial ecology knowledge and the use of polyphasic approaches in a complex ecosystem such as a food processing plant could be useful to characterize microbial reservoirs, improve targeted hygiene procedures, and lead to a better product quality all along the shelf life .