Reduction of Escherichia coli on Surfaces of Utensils and Development of a Predictive Model as a Function of Concentration and Exposure Time of Chlorine

Abstract

Cross-contamination to fruit and vegetables can readily occur through contaminated surfaces; thus, there is a need to develop methods to inactivate microorganisms on the surfaces of various materials. The aim of this study was to develop methods to reduce the levels of Escherichia coli on the surfaces of various materials and to develop a predictive model as a function of chlorine concentration and exposure time. The reduction of E. coli on the surfaces of stainless steel, plastic, wood, rubber, glass, and ceramic at various chlorine concentrations (0-200 ppm) after a 0-5-min exposure was evaluated. The surface treatment at the maximum chlorine concentration (200 ppm) over a 5-min exposure reduced the E. coli contamination levels to 5.30, 5.18, 3.34, 4.69, 5.05, and 5.53 log CFU/cm(2) on the surfaces of stainless steel, plastic, wood, rubber, glass, and ceramic, respectively. Using these results, predictive models for the reduction of E. coli on surfaces of various materials using chlorine treatment were developed. Each model was significant (p<0.05) and defined as fit by the lack of fit and probability of normal residuals. It has measured the R(2) value to 0.9746. Therefore, the models presented in this study could be used to determine the minimum concentrations of chlorine and exposure times needed to control E. coli on the surfaces of various materials.