Communication Dans Un Congrès Année : 2017

Controlling Negative Flora In Dairy Industry With Positive Biofilms?

Résumé

Biofilms forming in dairy installations can dramatically affect the quality of dairy products and cause technologic and health issues. Installing Lactic Acid Bacteria (LAB) in milking machines (MM), like Lactococci, to form positive biofilms and compete with negative flora would be an interesting solution. In a previous work, 37 strains of Lactococcus lactis ssp lactis (L. lactis) were isolated from raw goat milk. These strains exhibited a wide genetic variety and various physicochemical surface properties. Among them, 7 strains were tested in a shear-stress flow chamber to evaluate their adhesion to stainless steel (the main component of MM). EIP20F and EIP08G (hydrophobic and low electronegative charge), the most adherent strains on stainless steel, were selected for this study. The aim of this work was to study capacity of EIP20F and EIP08G to form biofilms and to test their capacity to control Pseudomonas sp. (CIP6913T, negative flora). After optimizing the culture medium to obtain reproducible single species biofilms, mixed species biofilms were generated. When L. lactis and Pseudomonas were inoculated simultaneously, no difference in bacterial density was observed compared to single species biofilms, no matter what the substratum material was (polystyrene or stainless steel). When L. lactis was inoculated before Pseudomonas (24 to 48 h), the same bacterial density was obtained after 24 h to 72 h of incubation. These results were confirmed with environmental isolates of Pseudomonas (P. fluorescens and P. korensiis). Finally, confocal microscopy revealed that both species coexisted together, one forming a thin layer on the surface (L. lactis) and the other one forming bulky aggregates on top of this layer (Pseudomonas). This study demonstrates that EIP20F and EIP08G are not good candidates to control Pseudomonas in MM in spite of their biofilm forming capacities. Other L. lactis with different surface properties should be tested to address this issue.

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Dates et versions

hal-05132871 , version 1 (27-06-2025)

Identifiants

  • HAL Id : hal-05132871 , version 1

Citer

Gwenaelle Jard, Sophie Pécastaings, Ibrahima Drame, Mickaël Castelain, P. Schmitz, et al.. Controlling Negative Flora In Dairy Industry With Positive Biofilms?. Eurobiofilms, Sep 2017, Amsterdam, Netherlands. ⟨hal-05132871⟩
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