Modified Enzymatic Assays for the Determination of Histamine in Fermented Foods

Histamine is a biogenic amine, produced in spoiled fish and some fermented products, which causes a foodborne disease similar to an allergic reaction. Because regulatory levels on histamine in food have been set by many countries or organizations, a quick and accurate analysis of histamine is of great interest. An enzymatic histamine determination method on the basis of a colorimetric assay has been used to detect histamine for raw and canned tuna due to its simplicity and rapidity. However, note that some compounds in fermented foods interfere with assay results. In this study, the pretreatments and conditions of the assay for fermented foods were evaluated. Lowering the reaction temperature from 37 to 23 degrees C was considerably effective in reducing the interference. As a result, histamine in salami and sauerkraut (>= 5 to 10 mg/kg) could be determined with a 25-fold dilution, as in the manufacturer's instructions. Histamine in soy sauce (>= 10 to 20 mg/L) could also be determined with a 100-fold dilution. Removing fat and protein in cheese samples by using perchloric acid with a resultant 25-fold dilution and removing polyphenol with polyvinylpolypyrrolidone for red wine with a fivefold dilution were feasible; the limits of quantification were 5 mg/kg and 1 mg/L, respectively. Good recovery rates, precision repeatability, and correlations with a high-performance liquid chromatography method were confirmed. These protocols are expected to be applicable for histamine determination in various foods and useful for preventing histamine food poisoning.