Efficacy of chlorinated and ozonated water in reducing<i>Salmonella typhimurium</i>attached to tomato surfaces

Abstract

The purpose of this study was to compare chlorinated and ozonated water in reducing Salmonella typhimurium inoculated onto fresh ripe tomatoes. Surface-inoculated tomatoes were immersed/sprayed with chlorinated (200 mg l(-1)) and ozonated water (1 and 2 mg l(-1)) under 2 and 100 nefelometric turbidity units (NTU). Contact times were 120 and 30 s for immersing and spraying applications, respectively. Immersing in chlorinated water and low turbidity resulted in the most effective application with 3.61 log(10) bacterial reduction, while 1 and 2 mg l(-1) of ozone reduced 2.32 and 2.53 log(10), respectively. High turbidity and chlorine reduced the bacterial counts by 3.39 log(10), while 1 and 2 mg l(-1) of ozonated water and low turbidity reduced the bacteria by 1.48 and 1.92 log(10), respectively. Spraying chlorinated water reduced bacteria by 3 log(10), and ozonated water at 1 and 2 mg l(-1) reduced counts by 1.84 and 2.40 log(10), respectively. No statistical differences were found between chlorine and ozone (2 mg l(-1)) during spraying applications (p < 0.05). The use of ozonated water both in immersing and spraying applications is suggested when water turbidity remains low.