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 μl (10 μl/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 blueberries 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.

► Novel ozonated water, FIT solution, and EO water are friendly home-use sanitizers.
► Ozonated water, FIT solution, and EO water inactivate Escherichia coli 157:H7 on blueberries.
► FIT and EO water are comparable to bleach in killing pathogen in wash solution.
► FIT, EO water and bleach could minimize cross-contamination in food preparation area.