Indeed, Shewanella putrefaciens, Pseudomonas spp., Photobacterium phosphoreum, Brochothrix thermosphacta, Aeromonas spp. and lactic acid bacteria are not only members of the microbial association found in fish from temperate waters (Koutsoumanis and Nychas 1999;Dalgaard 2000), but they also contribute significantly to the spoilage of fish stored under different conditions. However, not all Keywords 16S rRNA, fish preservation, fish spoilage, modified atmosphere packaging, sodium dodecyl sulfate electrophoresis, taxonomy. AbstractAims: To study the diversity of Shewanella population in Sparus aurata fish harvested in the Aegean Sea, as well as to elucidate the influence of fish storage conditions on the selection in Shewanella strains. Methods and Results: A total of 108 strains of Shewanella spp. were isolated from Sparus aurata during storage under various conditions. Conventional phenotypic analysis along with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole cell proteins and 16S rRNA sequence analysis were used for the characterization of the strains. Numerical analysis of whole cell protein profiles showed that the isolates were separated into two distinct clusters A and B with 47% similarity. Cluster B was further subdivided into two subclusters B1 and B2 with 70% similarity. One strain could not be assigned to any of these groups. The different ability of isolates to utilize deoxycholate, d-saccharate, d-glucuronate, n-acetyl-glycosamine, d-maltose, gluconate and citrate, as well as the different type of metabolism on the Hugh and Leifson medium distinguished the different Shewanella biogroups, as these were defined by the SDS-PAGE analysis. Representative strains from the three biogroups were further investigated by 16S rRNA sequence analysis and showed more than 99AE4% similarity. Conclusions: Significant similarities between the isolates and the type strains of S. baltica, S. putrefaciens and S. oneidensis at both phenotypic and molecular level signalize that the new isolates are closely related with the above Shewanella species, but do not provide a clear evidence to which of these species they belong. Significance and Impact of the Study: The lack of information about the diversity of Shewanella population in Sparus aurata fish originated from Mediterranean Sea could be confronted using conventional phenotypic techniques, SDS-PAGE analysis of whole cell proteins and 16S rRNA sequencing.

Aims:  To identify lactic acid bacteria (LAB) present in Moroccan dairy products to establish and preserve their microbial species diversity. Methods and Results:  Thirty‐seven samples were collected from different farms. A total of 146 LAB were isolated and subjected to (GTG)5‐PCR analysis. Comparison of the profiles with data available at the Moroccan Coordinated Collections of Micro‐organisms allowed identification of 85 isolates. The remaining 61 were subjected to SDS‐PAGE analysis of whole cell proteins. Comparison of the profiles with data available at the Belgian Coordinated Collections of Micro‐organisms allowed identification of 43 isolates. Several of the remaining 18 isolates exhibited identical protein electrophoretic fingerprints. Therefore, eight representatives of them were subjected to partial pheS gene sequencing which allowed identification of all remaining isolates. In raw milk, six genera were found while in ‘lben’, three were found. This is the first report of Leuconostoc kimchii in dairy products. Conclusions:  LAB diversity was established using a stepwise polyphasic identification approach. It used the expertise of both research bodies involved in this study and proved to be cost‐effective for the identification of all isolates. Significance and Impact of the Study:  To establish LAB diversity in Moroccan dairy products which could be a source of strains with specific properties.

No abstract