Bacterial succession during curing process of a skate (Dipturus batis) and isolation of novel strains.
OBJECTIVE
To study the succession of cultivated and uncultivated microbes during the traditional curing process of skate.


RESULTS
The microbial diversity was evaluated by sequencing 16Sr RNA clone libraries and cultivation in variety of media from skate samples taken periodically during a 9-day curing process. A pH shift was observed (pH 6·64-9·27) with increasing trimethylamine (2·6 up to 75·6 mg N per 100 g) and total volatile nitrogen (TVN) (from 58·5 to 705·8 mg N per 100 g) but with relatively slow bacterial growth. Uncured skate was dominated by Oceanisphaera and Pseudoalteromonas genera but was substituted after curing by Photobacterium and Aliivibrio in the flesh and Pseudomonas on the skin. Almost 50% of the clone library is derived from putative undiscovered species. Cultivation and enrichment strategies resulted in isolation of putatively new species belonging to the genera Idiomarina, Rheinheimera, Oceanisphaera, Providencia and Pseudomonas. The most abundant genera able to hydrolyse urea to ammonia were Oceanisphaera, Psychrobacter, Pseudoalteromonas and isolates within the Pseudomonas genus.


CONCLUSIONS
The curing process of skate is controlled and achieved by a dynamic bacterial community where the key players belong to Oceanisphaera, Pseudoalteromonas, Photobacterium, Aliivibrio and Pseudomonas.


CONCLUSIONS
For the first time, the bacterial population developments in the curing process of skate are presented and demonstrate a reservoir of many yet undiscovered bacterial species.
Department of Food safety, Environment and Genetics, Matís ldt, Reykjavík, Iceland. eyjolfur.reynisson@matis.is
E
E
Reynisson
V
V
Thornór Marteinsson
R
R
Jónsdóttir
S H
SH
Magnússon
G O
GO
Hreggvidsson
D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D005516:Food Microbiology; D005519:Food Preservation; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000032:analysis; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017747:Seafood / Q000382:microbiology*; D012860:Skates, Fish / Q000235:genetics / Q000382:microbiology*
D012336:RNA, Ribosomal, 16S; D009584:Nitrogen