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Poster De Conférence Année : 2012

The use of a pilot scale loop system to reproduce microflora adhering to industrial stainless steel pipelines

Résumé

Persistent bacteria in processing sites are of great concern in food industry, causing continuous recontamination and thus yielding compromised food quality and safety, lost productivity and environmental issues. The aim of this study was to develop a tool to reproduce bioadhesion under industrial conditions in order to investigate the impact of successive stress exposure on adhering microflora and further optimize food formulation, industrial process and surface sanitation. A pilot scale loop system was used to reproduce adhering flora after circulation of liquid egg in stainless steel pipeline at refrigerated temperature. Inoculation of the system was performed either by the circulation of non-pasteurized liquid egg or by the introduction of contaminated probe surface or insert. After 9 days of continuous flow, stainless steel inserts and sections were removed and analyzed with various conditions of incubation. The identification of culturable (ana)aerobe psychrotrophic and mesophilic isolates was performed by 16SrDNA sequencing. Moreover, the detection of Bacillus species was also performed using the PCR based GeneDisc® plateform. After loop circulation of non pasteurized liquid egg, bacterial isolates recovered from stainless steel surfaces were mainly composed of Gram-negative bacteria such as Pseudomonas, Myroides and Aeromonas. Enterobacteria and lactic acid bacteria were as well identified but with a lower extend, while Bacillus species were only detected by GeneDisc® plate. When the loop system was inoculated with an insert preliminary left for 2 months in an industrial pipeline, the proportion of recovered Gram-positive flora was higher. Indeed, Corynebacterium, Enterococcus and Staphylococcus were identified from industrial surfaces. Even though this system might favour fast growing colonizers, correlation was found between bacterial diversity recovered from pilot scale system and industrial pipeline surfaces. It is interesting to note a shift of diversity recovered from surfaces when industrial surfaces were used to inoculate the loop, suggesting the survival and persistence of given species after consecutive steps of production/sanitation. This system is promising to further study bacterial removal and inactivation upon exposure to acid or biocide taking into account protection due to embedded structure or food residues.
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Dates et versions

hal-01136293 , version 1 (26-03-2015)

Identifiants

  • HAL Id : hal-01136293 , version 1
  • PRODINRA : 286996

Citer

Florence Postollec, Emeline Cozien, Anne Gabrielle Mahot, Sophie Jan, Florence Baron, et al.. The use of a pilot scale loop system to reproduce microflora adhering to industrial stainless steel pipelines. 23. International ICFMH Symposium, Food Micro 2012, Sep 2012, Istanbul, Turkey. 2012. ⟨hal-01136293⟩
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