Poisoning due to ingestion of foods with elevated levels of
biogenic amines (
histamine,
putrescine,
cadaverine, and
tyramine) is well documented.
Histamine fish
poisoning largely is due to growth of naturally occurring bacteria associated with scombroid fish species. A rapid and reliable method is needed to screen for the presence of
histamine-forming bacteria in fish. This study included a comparison of three methods for the detection of
histamine-producing bacteria. A total of 152
histamine-producing and non-
histamine-producing bacteria from multiple sources were screened using a modified Niven's
agar method, a potentiometric method, and a PCR-based assay targeting a 709-bp fragment of the
histidine decarboxylase gene.
Histamine production by bacterial isolates was confirmed by high-performance liquid chromatography (HPLC). Bacterial strains were categorized as producing high amounts of
histamine, low amounts of
histamine, or no
histamine. Of the 152 strains tested, 128 (84%) were positive with the Niven's
agar method, 73 (48%) were positive with the potentiometric technique, and 74 (49%) were positive with the PCR assay. Overall, a 38% false-positive rate was observed with the modified Niven's
agar method, although this method detected both low-
histamine and high-
histamine strains. There was a high degree of concordance (> 99%) between results of the potentiometric and PCR methods, but neither of these methods detected low-
histamine bacteria. These observations support the need for a simple and straightforward yet sensitive method for detecting
histamine-producing bacteria in seafood and environmental samples.