Ei. Lopezsabater et al., INCIDENCE OF HISTAMINE-FORMING BACTERIA AND HISTAMINE CONTENT IN SCOMBROID FISH SPECIES FROM RETAIL MARKETS IN THE BARCELONA AREA, International journal of food microbiology, 28(3), 1996, pp. 411-418
Incidence and diversity of histidine decarboxylating bacteria were det
ermined in samples of tunafish, bonito and mackerel purchased at diffe
rent retail markets. Histamine-forming bacteria occurred in a low prop
ortion and always accounted for less than 0.1% of the total bacterial
load in the fish samples studied. Similarly, histamine content in fish
samples also was low (< 25 ppm) and all of them met current histamine
standards established by the European Union. Histamine was found in 8
3.3% of the tested tunafish samples with an average of 8.9 ppm. In con
trast, none of mackerel samples and only 2 out of 12 of bonito showed
detectable amounts of histamine. Morganella morganii and Klebsiella ox
ytoca were the most active histamine formers under experimental condit
ions, and produced on average 2765 and 1415 ppm of histamine, respecti
vely, after incubation at 37 degrees C for 18 h. Some new histamine fo
rmers, such as Plesiomonas shigelloides, Enterobacter intermedium, Ser
ratia marcescens, Serratia plymuthica and Serratia fonticola, have bee
n identified. Especially Plesiomonas shigelloides would have an import
ant role within histidine decarboxylating bacteria because it was the
sole histamine former isolated that has frequently been associated wit
h the marine aquatic environment. However, only 8-340 ppm of histamine
was formed by these strains in laboratory trials.