The Monitoring And Control Technology Research Of Histamine In Aquatic Food

Histamine of aquatic foods is formed microbial decarboxylation of free histidine. Theingestion of high level histamine can lead to allergic-like food poisoning which is also calledscombroid.fish poisoning. It is common seen histamine caused food safety problems andresources wasting in processing and storage of aquatic products. Therefore, in this stady, apre-column derivatization with dansyl chloride reversed high performance liquidchromatographic (RP-HPLC) method was developed for the determination of histamine inaquatic foods. Histamine forming bacteria were isolated and identified from blue scad(Decapterus maruadsi) and chub mackerel (Scomber japonicus), then their characterization wasanalyzed. Effects of physical processing treatments, storage temperature, antimicrobials, cookingprocessing treatments and Maillard reaction treatment to histamine in aquatic products wasstudied for finding effective control methods of histamine.A pre-column derivatization with dansyl chloride reversed high performance liquidchromatographic (RP-HPLC) method was developed for the determination of histamine inaquatic foods. After extracted by trichloroacetic acid, derivatized with dansyl chloride，thesamples were separated by C18column, using a isocratic elution program with a mixture ofacetonitrile and ultra-pure water and the ultraviolet wavelength of254nm. The results showedthat the retention time of histamine was5.5min. The linear range of histamine was good in1~500μg/mL and the correlation coefficient was0.9999. The limit of detection (S/N=3) was0.5μg/mL and the limit of quantization (S/N=10) was1.0μg/mL. The repeatability of the instrumentwas good. The average recoveries of histamine at different concentration levels in blank sampleswere between84.01~101.92%. The level of histamine was detected in16aquatic products and19processing aquatic products. The results showed concentration of histamine was between0~682.22mg/kg.Two histamine forming bacteria were isolated from blue scad by using ahistamine-producing bacterium isolation medium and named as B2and B5, and a histamineforming bacteria was isolated from chub mackerel by the same method and named as Q4. B2, B5and Q4were Citrobacter freundii, Citrobacter braakii and Enterobacter aerogenes respectivelyidentified by16S rDNA sequence analysis, VETIK2Compact system and MALDI-TOF MS.Gram staining showed they were all gram negative bacteria. Growth curve showed these threestrains entered into logarithmic phase after2h and accessed to stable phase after8h at37°C.The histamine producing ability of3strains was Q4﹥B5﹥B2. The optimum temperature of B2, B5and Q4for histamine producing was35,37and35°C. The optimum pH of B2, B5and Q4for histamine producing was6.0,6.0and5.0. Histamine productions of B2, B5and Q4were4213.46mg/L,1057.10mg/L and469.76mg/L respectively after cultured48h at37°C. Amongdifferent antimicrobials, potassium sorbate and sodium diacetate could effectively inhibithistamine forming bacteria and its histamine producing ability.Heating, ultraphonic, ultraviolet radiation, microwave, high pressure steaming treatmentshad no effect on histamine, and histamine was stable in different pH conditions. Changes ofhistamine in tuna skipjack tuna, chub mackerel and blue scad were monitored under differenttemperature. The results showed that histamine contents of tuna skipjack tuna, chub mackereland blue scad reached8484.82,3760.35and2531.29mg/kg respectively after storage48h at25°C. Histamine contents of tuna skipjack tuna, chub mackerel and blue scad reached84.66,79.24and61.00mg/kg respectively after storage a week at4°C. There was no histamine detected inthe samples storage at-30°C, which revealed that low temperature storage could effectivelycontrol histamine producing in aquatic products. After soaked with0.1~0.5%potassium sorbateand sodium diacetate respectively and storage at ambient temperature (15±5°C) for24h, thehistamine of mackerel was determined. The results showed that the histamine contents were only2.27and3.79mg/kg after soaked with0.3%potassium sorbate and0.3%sodium diacetaterespectively, which was indicated that potassium sorbate and sodium diacetate solution soakingtreatment could effectively control histamine of mackerel.The effect of Maillard reaction treatment on histamine was studied. After Maillard reactionbetween glucose and histamine at60°C for6h, histamine concent had reduced94%. With thetemperature improving, Maillard reaction between glucose and histamine got faster. The resultsindicated that Maillard reaction could effectively eliminate histamine. The mackerel was treatedwith steaming, frying and microwave methods respectively, and found out there was no effect onhistamine in mackerel. However, after soaked with2.0%glucose solution, then treated with thesame methods above, the histamine concent of mackerel was reduced and the steaming methodhad best effect. Histamine was reduced69%, from1074.31mg/kg to332.14mg/kg, A methodfor decreasing histamine in canned mackerel was invented through soaked with2.0%salt and3.0%glucose solution and using Maillard reaction in steaming and high pressure steamingprocess.