A RAPID DIPSTICK TEST FOR HISTAMINE IN TUNA

This study describes the production of a solid phase assay (dipstick test) for histamine in tuna based on the coupling of diamine oxidase to a peroxidase/dye system. The optimized dipstick preparation consisted of a diamine oxidase/peroxidase/Stabilcoat mixture layered onto a tetramethylbenzidine color strip. The assay was linear to 1.0 mM histamine (RSQ=0.994) and the minimum detectable concentration was 0.07 mM corresponding to 2.3 mg% in tuna extracts. Quality control samples gave intra and interassay precisions of 9.14-9.84 %CV and 7.08-13.86 %CV respectively. Similarly, the assay was accurate (p > 0.05) for both low and high controls. Histidine and cadaverine did not interfere with the assay whereas putrescine reacted slightly with the dipstick. Histamine determinations of fresh and spoiled tuna gave good agreement between the dipstick method and both the official reference and modified AOAC flurometric methods.