Isolation of ice-nucleating active bacterium from mackerel and its properties |
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| Authors: | MEI-LING CHEN TZE-KUEI CHIOU SHANN-TZONG JIANG |
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| Institution: | Affiliation: Department of Food Science, National Taiwan Ocean University, Keelung 202, Taiwan |
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| Abstract: | ABSTRACT: An ice-nucleating bacterium, designated MACK-4, was isolated from ice-stored mackerel ( Scomber australasicus ) and identified as a Pseudomonas fluorescens . The optimal temperature and pH for its growth in nutrient broth with 2.5% glycerol (NB-G) were 15°C and 6.5, respectively. The maximal ice-nucleating activity (INA) was obtained after 54 h incubation at 15°C. However, the INA was almost completely lost after 48 h incubation at 25°C or higher. The growth and INA decreased with increase of NaCl added in NB-G within 0.0–4.0%. The INA of MACK-4 was very stable at 5–25°C, pH 4.0–9.5, while that of isolated ice-nucleating matter from MACK-4 was stable at 5–25°C, pH 5.5–9.0. |
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| Keywords: | ice-nucleating activity (INA) number of ice nuclei INA/mL |
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