Histamine-Related Hygienic Quality and Isolation of Histamine-Forming Bacteria and Histamine-Degrading Bacteria in Salted Seafood Products

• Main Authors: LIU, FANG-LING, 劉芳伶
• Other Authors: Tsai Yung-Hsiang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/43981569335863967480

碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 99 === The fifty-seven salted seafood products sold in the fishing village stores in Taiwan, including salted fish product, salted mollusk product and salted shrimp product, were tested to determine the occurrence of histamine, histamine-forming bacteria and histamine-degrading bacteria. The results showed that salted fish product, salted mollusk product and salted shrimp product had average levels of pH for 5.81, 5.11 and 6.21, salt content for 14.1, 9.49 and 8.43%, water activity for 0.77, 0.84 and 0.86, total volatile basic nitrogen for 99.0, 55.6 and 102 mg/100g, and aerobic plate count for3.14、3.02 and 5.09 log CFU/g, respectively. None of these samples contained total coliform and Escherichia coli. The average salt content of salted fish samples was significantly (P<0.05) higher than that of salted mollusk samples and salted shrimp samples, whereas the average Aw value in the salted fish samples was the lowest (P<0.05). Although the average content of each of nine different biogenic amines in all samples was less than 5.0 mg/100 g, 10.5% (6/57) of tested samples had the histamine content greater than the 5.0 mg/100 g allowable limit suggested by the U.S. Food and Drug Administration. One histamine-producing bacterial strain capable of producing 78.5 ppm of histamine in trypticase soy broth supplemented with 1.0 % L-histidine (TSBH) was identified as Bacillus megaterium. The B. megaterium isolate was a halotolerant bacterium with growing well at elevated NaCl concentration to 15% in TSBH medium. Besides, it had a consistent ability to produce >300 ppm of histamine at 10% NaCl concentration in TSBH medium after 72 h. Furthermore, eight histamine-degrading bacteria isolated from salted fish samples and salted mollusk samples were identified as Rummeliibacillus stabekisii (1strain), Agrobacterium tumefaciens (1 strain), Bacillus cereus (2 strains), B. polymyxa (1 strain), B. licheniformis (1 strain), B. amyloliquefaciens (1 strain), B. subtilis (1 strain). Among them, B. polymyxa degraded histamine up to 100% in histamine broth. Therefore, the well range of temperature, pH and salt concentration for growth and histamine degradation of B. polymyxa were 25-37℃, pH 5-9 and 0.5-5% NaCl, respectively. However, the optimal growth and histamine dehydrogenase activity of B. polymyxa were at 30℃, pH 7 and 0.5% NaCl for 24 h incubation.