A RAPID DIPSTICK TEST FOR HISTAMINE IN TUNA

This study describes the production of a solid phase assay (dipstick t est) 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 tet ramethylbenzidine color strip. The assay was linear to 1.0 mM histamin e (RSQ=0.994) and the minimum detectable concentration was 0.07 mM cor responding to 2.3 mg% in tuna extracts. Quality control samples gave i ntra and interassay precisions of 9.14-9.84 %CV and 7.08-13.86 %CV res pectively. Similarly, the assay was accurate (p > 0.05) for both low a nd 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.