Histamine Related Hygienic Quality and Determination of Melamine in Fish Meals

• Main Authors: Chen, Yun Yun, 陳筠芸
• Other Authors: 蔡永祥博士
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/54130573351266883731

碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 99 === The purpose of this study is to understand the histamine related quality of imported fish meal and fish soluble concentrates (FSC). Forty fish meals and five FSCs imported from foreign country were collected and tested to determine the biogenic amine and histamine-forming bacteria. The average levels of water activity (0.8), water content (39.9%), salt content (7.32%), total volatile basic nitrogen (TVBN) (150.7 mg/100g) and hydrochloric acid insoluble content (0.84%) in FSC samples were significantly higher than those of fish meal samples, whereas the average levels of crude fat (3.94%) and crude protein (40.6%) in FSC samples were significantly lower than those of fish meal samples. None of these samples contained Escherichia coli and Salmonella spp. The average contents of putrescine, cadaverine, histamine and tyramine in tested samples were more than 1.40 mg/100g. Four tested fish meal samples (10%, 4/40) and 1 tested FSC sample (20%, 1/5) had histamine levels greater than 20 mg/100g. Five histamine-producing bacterial strains isolated from fish meal samples producing 1.31~6.21 ppm of histamine in trypticase soy broth supplemented with 1.0% L-histidine (TSBH) were identified as Bacillus licheniformis (three strains), B. amyloliquefaciens (one strain) and B. subtilis (one strain). Moreover, a method for the determination of melamine in fish meal by high performance liquid chromatographic with photodiode array detector (HPLC-PDA) was developed. The correlation coefficient for the standard curve of melamine between 0.25 and 4 ppm was 0.9999. The coefficients of variation of melamine in intraday and interday analysis were less than 5 %. Recovery of melamine from fish meal sample ranged from 84.0% to 91.9%. The detection of limit (LOD) and detection of quantitation (LOQ) of melamine were 0.5 ppm and 1.5 ppm, respectively. To evaluate the recovery effects of different extraction methods for melamine in fish meal, it was found that mixed protein precipitant, including potassium ferrocyanide, zinkacetat-dihydrate and acetic acid glacical, could reduce the background signal of the chromatography for melamine. In addition, the application of 25% ACN solution substituted for 50% ACN and dichloromethane for extraction in purification steps did not affect the recovery of melamine in HPLC analysis. Only one fish meal sample (squid viscera powder) had melamine content of 7.3 ppm in 45 imported fish meal samples by HPLC analysis and LC/MS/MS confirmation analysis.