| Summary: | 碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 100 === Chlorine dioxide (ClO2) is a strong oxidizing and sanitizing agent. Comparing with the sodium hypochlorite, ClO2 is less reactive with organic compounds to form trihalomethanes, a carcinogen. In addition, ClO2 evaporates quickly and leaves no toxic residue. Thus, it has been approved by the regulatory agencies in Taiwan. Histamine is a cause agent for the commonly occurring food poisoning, scombroid poisoning, and an enzymatic product produced by contaminated bacteria. Those bacteria are able to produce an enzyme, histidine decarboxylase, to convert histidine to histamine in fishes containing high amount of free histidine. Histamine is thermal stable and difficult to be destroied by heat. Therefore, the critical procedure to prevent histamine poisoning is to disinfect or inhibit the growth of histamine-producing bacteria. Thus, the objectives of this study are to evaluate the inhibitory efficacy of chlorine dioxide on the histamine-producing bacteria and understand the various resistances between the histamine-producing bacteria to the chlorine dioxide. Five histamine-producing bacteria, Enterobacter aerogenes, Staphylococcus capitis, Raoultella ornithinolytica, Morganella morganii and Proteus vulgaris were treated with different concentrations of ClO2 (0.1, 0.5, 1, 5 ppm) at treatment time (30, 60, 90, 120 sec) in phosphate buffer. Minimal bactericidal concentrations (MBC) of chlorine dioxide against E. aerogenes, S. capitis, M. morganii, and P. vulgaris were 5 ppm at 30 sec treatment and the MBC of chlorine dioxide against R. ornithinolytica was 1 ppm at 30 sec. Thus, R. ornithinolytica was the most sensitive species and other four bacteria had the same sensitivity to ClO2. The second stage of this study treated marlin flesh with different concentrations of ClO2 (25, 50, 100 ppm) for 5 min, then stored at 4, 15 and 25℃. NaOCl (100 ppm) and sterile water were used as controls. Total plate count, total volatile based nitrogen (TVBN), pH, histamine contents were analyzed. Results showed using ClO2 reduced the bacterial growth and TVBN production at 15 and 25℃. In addition, histamine production was reduced by applying ClO2 and NaOCl. When marlin flesh was treated with 25 ppm ClO2, it took one more day (from 1 to 2 days) to reach the histamine limit set by the US FDA (5 mg/100 g) at 15℃.
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