1. Applications

- The Histamine Check Swab (Kikkoman, code 60448) is to be used to assay histamine contained in food samples by means of a colorimetric reaction. Assay results can be checked by the changes in reagent color. Comparing changes in color with the color chart will provide a rough understanding of histamine content.

- This product simplifies the process of identifying histamine concentration in assay samples but it is neither intended as a precise quantification of histamine or an official analytical method.

- This product may not determine accurate histamine content due to false positive reaction depending on the sample. False positive means the changing color of the reagent despite the absence of histamine in the sample. Please verify whether your sample can be assayed by this product by comparing other histamine assay method.

2. Measurement Principles

- The assay method of this product incorporates enzymes that act specifically on histamine. In the presence of tetrazolium salt and electron acceptors, histamine dehydrogenase acts on tetrazolium salt to produce formazan dye (purple).

- As formazan dye concentration varies depending on histamineconcentration, a rough understanding of histamine concentration in samples can be obtained by making a comparison with the color chart.

3. Product Features and Product Specifications

-This product comprises a swab, extraction reagent, and colorimetric reagent designed to determine histamine content. With this assay kit, there is no need for any other equipment such as a spectrophotometer to visually check histamine content in samples.

- Specificity: This assay method is not affected by other amines contained in specimens, such as cadaverine or putrescine. However, coloration may occur even in the absence of histamine depending on assay samples and pretreatments (hereinafter "false positive").

- Take the product out of the refrigerator and bring it up to room temperature (18 - 30℃). After being brought up to room temperature, the product should be used as quickly as possible. Dilute an assay sample by two to five times. Solid form assay samples should be minced. False positives may be prevented by heating the diluted sample.

- Pull out the swab stick from the main body.

- Soak the swab in the diluted sample. If the assay sample is a solid form, do not allow any solid object to stick to the swab.

- Return the swab stick to the main body, and push it through all the way into the main body.

- Hold the main body and shake it. The leftover colorimetric reagent will fully dissolve.

- After five minutes, check the coloration of the reaction solution. A rough understanding of the histamine concentration can be obtained by making a comparison of the color with the color chart

4.2. Assay procedure Fish sauce

- Dilute the fish sauce with water by five times.

- Full out the swab stick from the main body.

- Soak the swab in the diluted sample.

- Return the swab stick to the main body, and push it through all the way into the main body.

- Hold the main body and shake it. The leftover colorimetric reagent will fully dissolve.

- After five minutes, check the coloration of the reaction solution. A rough understanding of the histamine concentration can be obtained by making a comparison of the color with the color chart.

4.3. Identification of histamine content in an assay sample

- Histamine content in an assay sample (ppm) = Histamine content identified in comparison with the color chart (ppm) x Dilution factor*

* "multiply 5" if sample is diluted by five time

5. Precauntions for use

- This product is for purpose of in-house screening and research applications. It is neither intended as a precise quantification of histamine or an official anaalytical method.

- Histamine is prone to adhere to glass; therefore, apparatus made of plastic should be used for preparation.

- False positive and inaccuracy in histamine content assay may occur depending on assay samples and pretreatments. Please use another assay method, if accurat histamine content must be identified.

- Please make sure to follow the instruction manual attached to the product prior to use.

- Bring this product up to room temperature (18 to 30 celsius) prior to use.