Effect of aqueous ozone on microbial and physicochemical quality of Nile tilapia processing

Abstract

The efficiency of ozonated water as a disinfectant for removing microorganisms in freshwater fish was investigated. Nile tilapia samples (whole and fillets) were immersed in cold water (11°C), without ozone (0 ppm—control) and with ozone (0.5, 1.0, 1.5 ppm) for 0, 5, 10, and 15 min. Microbiological and physicochemical parameters were evaluated. The most efficient ozone concentration to reduce microbiological contamination of the whole tilapia was 1.5 ppm (88.25% of reduction) at 15 min of contact. Ozonated water at 1 and 1.5 ppm showed the greatest reduction (77.2 and 79.49%, respectively) in the fillet treatment. Neither the pH nor the color of fillets was influenced by ozonated water treatment; however, a small triggering of lipid oxidation process was observed by the increase in the TBARS value. These results prove that ozonated water was effective in reducing the microbial load and maintain the quality of fish, with low cost. Practical applications As an environmentally friendly disinfectant, ozone now is being studied as an alternative to chlorine sanitizers in many segments of the food industry. The use of ozone as a superficial disinfectant of meat surfaces has been reported in the fish industry. Few studies on the use of ozone in farmed freshwater fish have been reported. Ozonated water treatments improve the quality and extend the shelf life of fish. We evaluated and proved the microbial efficiency of ozonated water during Nile tilapia processing, and indicate that fillet quality was not adversely affected by ozone treatment.