Silva, Manuela V. daPinho, OlíviaFerreira, IsabelPlestilov, Linda2011-10-222011-10-222002SILVA, Manuela V. da - Production of histamine and tyramine by bacteria isolated from Portuguese vacuum-packed cold-smoked fish. Food Control. ISSN 0956-7135. Vol. 13 (2002), p. 457–461http://hdl.handle.net/10400.14/6829An agar medium containing histidine or tyrosine incubated anaerobically was used for detecting the decarboxylating activity of bacteria isolated from Portuguese vacuum-packed cold-smoked fish during chilled storage. The capacity of each bacterial isolate to produce histamine and tyramine was studied at 25 and 5 C incubated for 48 h and 10 days, respectively. More strains produced histamine and tyramine at 25 C compared with 5 C although lactic acid bacteria (LAB) strains exhibited similar results at the two different temperatures. Tyramine was produced by majority of the isolates tested although very low concentrations were produced at 5 C as confirmed by high-pressure liquid chromatography (HPLC). Tyrosine-agar was shown to be a good indicator medium for detection of bacteria that produced high levels of tyramine, since typical colonies surrounded by a translucent halo were easily recognised. LAB identified as Lc. Lactis lactis 1 and Carnobacterium divergens were detected as tyramine-producing bacteria. Acinetobacter spp. and Pseudomonas spp., isolated from all Portuguese smoked fish products, were negative on histidine-agar, but HPLC identified considerable quantities of histamine produced in a broth medium.engHistamineTyramineBiogenic aminesDecarboxylating bacteriaCold-smoked fishjournal article