Production of histamine and tyramine by lactic acid bacteria isolated from vacuum-packed sugar-salted fish

The incidence of histamine- or tyramine-producing lactic acid bacteria was examined in several products of vacuum-packed sugar-salted fish (salmon, halibut, mackerel). No histamine-producing isolates were observed, whereas the majority of tyramine-producing isolates were identified as Carnobacterium spp. These organisms were shown to be important members of the microbial flora during storage of vacuum-packed sugar-salted salmon at 5°C. The amount of tyramine produced was reduced by lowering the temperature from 9°C to 4°C for all of five strains of carnobacteria or lactobacilli. The majority of tyramine was produced during the exponential growth phase for Carnobacterium piscicola N 5 and Lactobacillus viridescens N 69. The ability of these bacteria to produce tyramine may be used as an index of microbial quality/acceptability of stored vacuum-packed sugar-salted fish.