Title: The effect of different temperatures on the growth of Vibrio cholerae, total viable microorganisms and hydrogen sulphide (H2S) producing bacteria

The aim of this project is to study the effects of different temperatures on growth of Vibrio cholerae, total viable microorganisms and hydrogen sulphide (H2S) producing bacteria. The study was conducted in two phases, in the first phase (experiment I) a sample of minced redfish was contaminated with V. cholerae and stored at different temperatures of -1.5°C, 0°C, 2°C, 4°C, 8°C and 17°C respectively. In this experiment V. cholerae was not detected. In the second phase (experiment II), 1 kg of redfish mince was contaminated with 1 ml of pure strains of V. cholerae and stored at 0°C, 8°C, 17°C, 22°C, 25°C and 30°C. Only V. cholerae was measured in this study. For V. cholerae two procedures were used; alkaline peptone water (APW) enrichment and direct inoculation of thiossulpate citrate biles salts sucrose agar (TCBS). Superchilled storage improved the shelf-life of minced redfish by 6 – 10 days compared with traditional chilled mince at 0°C. V. cholerae entered a viable but nonculturable state during storage time at low temperature but did grow well at high temperatures. However, higher numbers of V. cholerae counts were detected in APW enrichment than direct inoculation of TCBS agar. At high storage temperatures, bacterial growth was much faster than at low storage temperatures.