Biogenic amine production by bacteria isolated from ice-preserved sardine and mackerel

The occurrence of in vitro production of biogenic amines in bacteria isolated from ice-preserved sardine and mackerel was studied. Biogenic amine production was investigated by means of amino acid decarboxylation by growth on decarboxylase differential medium, biogenic amine detection by thinlayer chromatography (TLC) and decarboxylase gene detection by PCR. Decarboxylase medium overestimate the number of biogenic amine-producer strains, as the production of amine was confirmed by TLC in only five out the 17 presumptive strains. On the producer strains, PCR was used to confirm the presence of the genes encoding the amino acid decarboxylase responsible for the synthesis of these amines. Moreover, biogenic amine-producer bacteria were molecularly identified by sequencing their 16S rRNA. Form sardine, enterobacteria producing simultaneously several biogenic amines were isolated. A Kluyvera intermedia strain producing histamine, putrescine and cadaverine, and an Enterobacter asburiae strain producing only the diamines cadaverine and putrescine were identified. From mackerel, lactic acid bacteria from the Enterococcus durans species producing tyramine were isolated. This study constitutes the first description of the presence on these putatively harmful species on ice-preserved sardine and mackerel.
This work was supported by grants RM2008-00002 (Instituto Nacional de Investigación Agraria y Alimentaria), AGL2008-01052, Consolider INGENIO 2010 CSD2007-00063 FUN-C-FOOD (Comisión Interministerial de Ciencia y Tecnología), S2009/AGR-1469 (ALIBIRD) (Comunidad de Madrid), Tunisian Ministry of High Education and Scientific Research and Programa de Cooperación Interuniversitaria e Investigación Científica (AECI), Ministerio de Asuntos Exteriores y Cooperación, Spain (B/019335/08). We are grateful to M. V. Santamaría and J. M. Barcenilla. J. A. Curiel and G. Landeta are recipients of predoctoral fellowships from the I3P-CSIC and CONACyT, respectively.