Disinfection of effluent from fish slaughteries

The purpose of this study was to evaluate methods for inactivation of fish pathogens in outlet water from fish slaughteries. The effect of three disinfectants, namely sodiumhypochlorite, heat and photozone, were tested on two fish pathogens, Vibrio anguillarum and Yersinia ruckeri. Outlet water was incubated with the test bacteria for 24 h prior to use, and contained in the area of 10 6–10 9 CFU (Colony Forming Units) per ml. The following doses gave 100% inactivation of the test bacteria: 30 min exposure to 250 ppm sodiumhypochlorite, 60°C for 2 min, 72°C for 15 s and a photozone generated redox potential of approximately 550 mV for 30 min. The following doses resulted in 100% inactivation of all bacteria in the outlet water: 30 min exposure to 350 ppm sodiumhypochlorite, 72°C for 15 s and a photozone generated redox potential of approximately 550 mV for 30 min.