Inactivation kinetics of foodborne spoilage and pathogenic bacteria by ozone

Ozone was tested against Pseudomonas fluorescens, Escherichia coli O157:H7, Leuconostoc mesenteroides, and Listeria monocytogenes, When kinetic data f rom a batch reactor were fitted to a dose-response modeli, a 2-phased linea r relationship was observed. A continuous ozone reactor was developed to en sure a uniform exposure of bacterial cells to ozone and a constant concentr ation of ozone during the treatment. Survivors plots in the continuous syst em were linear initially, followed by a concave downward pattern. Exposure of bacteria to ozone at 2.5 ppm for 40 s caused 5 to 6 log decrease in coun t. Resistance of tested bacteria to ozone followed this descending order: E . coli O157:H7, P. fluorescens, L. mesenteroides, and L. monocytogenes.