碩士 / 國立高雄海洋科技大學 / 水產食品科學研究所 / 101 / The 103 raw and 34 cooked fish materials were collected from school kitchen of elementrary and middle school in Kaohsiung city from August 2011 to June 2012. Of 103 raw samples, one sample (0.97%, 1/103) in total volatile basic nitrogen (TVBN) was greater than the regulations of the food sanitary standard (25 mg/100g). There were 21.36% (22/103) of raw samples in aerobic plate count (APC) which was higher than the regulations of the food sanitary standard (6.47 log CFU/g). Regarding the cooked fish samples, all cooked samples were all qualified, indicating that the sanitary quality in cooking fish products at school kitchen was good. In addition, 25 histamine-producing bacteria capable of producing 5.7-142.6 ppm histamine in 1% of histidine in TSB medium were isolated from 103 raw fish samples. The Pangasius meat samples that had been collected from school kitchen were identified as catfish (Pangasius hypophthalmus) and harvested from Mekong River in Southeast Asia.
Furthermore, the histamine-producing bacterium isolated from Pangasius meat was identified as Macrococcus caseolyticus by polymerase chain reaction (PCR) direct sequence analysis. The Macrococcus caseolyticus 3-2 was spiked into the Pangasius meat and divided into non-inoculated group and inoculated group (5 log CFU/g). Both groups were stored at different temperatures (-20, 4, 15, 25 and 35℃), and had been analyzed to examine the change of the histamine-related quality in fish meat. The results showed that the pH values were increased by time increased; thereafter the pH values gradually became stable. The results showed that when the Pangasius meat stored above 25℃, the histamine-producing bacteria will rise rapidly, however, when that stored at 4 ℃ the bacteria growth will be inhibited. In TVBN content, the production of TVBN could be retarded when stored below 15 ℃. In addition, the inoculated samples were stored at 35 ℃ and 25 ℃ for 6 hours and 12 hours, respectively, and the TVBN contents in both samples were greater than 25 mg/100 g. The non-inoculated samples were stored at 35 and 25 ℃ for 2 days, and the TVBN content had reached the limits (25 mg/100 g). In histamine content, the inoculated samples stored at 25 and 35 ℃ for 12 hours and non- inoculated samples stored at 35 ℃ for 1 day and 25 ℃ for 2 days, formed histamine levels which was greater than the hazard level (50 mg/100 g) set by the US FDA. However, the growth of histamine-forming bacteria and histamine production were inhibited at 4℃. Although histamine formation was stopped by frozen storage, once the frozen samples were thawed and stored at 25℃, histamine started to accumulate rapidly. Therefore, this result suggested that Pangasius meat should promptly be stored at 4℃ below to prevent the risk of histamine poisoning.
| Identifer | oai:union.ndltd.org:TW/101NKIMT084027 |
| Date | January 2013 |
| Creators | Huang,Ling-Ying, 黃怜瑩 |
| Contributors | Yung-Hsiang, Tsai, 蔡永祥 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 104 |
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