A rapid colorimetric sensing unit for histamine content of mackerel using azo reagent

Histamine is a chemical hazard widely found in fishes of Scombridae family during long time storage or at improper temperature. In this study, a novel colorimetric method is proposed for determination of histamine in fish flesh. Azo reagent was selected as the indicator based on the characteristic spectrometry of chromogenic sensing materials reacted with histamine solution and the theoretical research. The colors of homemade colorimetric sensing units changed slightly from yellow to orange red and pink while the concentration of histamine varied from low to high. The Gray values of units were chosen for statistical and quantitative analysis. The relationship between Gray values and the histamine content were established based on linear regression. The results of the regression showed a high correlation and the calibration correlation coefficient was 0.9926. The results indicated that the homemade sensing unit could be regarded as a feasible way for simple and rapid detection of histamine in aquatic products. Practical applications Histamine is a chemical hazard widely found in fish of Scombridae family during long time storage and under improper storage temperature. In this study, a novel colorimetric method is proposed for determination of histamine in fish flesh. This method simplifies the detection procedure of fish histamine and shortens the detection time. The results indicated that the homemade sensing unit provided a feasible way for simple and rapid detection of histamine in aquatic products. This colorimetric sensing unit could be applied to rapidly monitor aquatic products by government testing agencies and food companies.