Reducing microbiological safety risk on blueberries through innovative washing technologies

The objective of this study was to determine the efficacy of novel home-use sanitizers (ozonated water, FIT solution, and EO water) in killing Escherichia coli O157:H7 on blueberries compared to common bleach solution and tap water. Blueberries samples (6 berries; ca. 10 +/- 1 g) were spot-inoculated with 60 mu l(10 mu l/berry) of a mixture of 5 strains E. coli O157:H7 (ca. 8-9 log CFU/ml) and treated in sanitizers for 1 -5 min. The greatest reductions of the pathogen (4.4-4.8 log CFU/g) were achieved by treating blueberries in bleach solutions (100 mg/l free chlorine), followed by EO water (30 mg/l free chlorine; 3.9-4.4 log CFU/g), FIT solution (3.3-4.6 log CFU/g), ozonated water (1.5 mg/l ozone; 2.3-3.5 log CFU/g), and tap water (1.9 -2.7 log CFU/g). In general, increasing treatment time from 1 to 5 min significantly increased the reduction of the pathogen, except for the bleach solution. In most cases, FIT solution, EO water, and bleach solution inactivated E. coli O157:H7 in treatment solutions after use. Application of novel sanitizers to wash blue-berries at home and food services could reduce the risk of E. coli O157:H7 that may attach to the berries and minimize cross-contamination during preparation of foods. (C) 2013 Elsevier Ltd. All rights reserved.