Decontamination of Escherichia coli O157:H7 and Salmonella enterica on Blueberries Using Ozone and Pulsed UV-Light

Authors

  • K.L. Bialka,

    1. Author Bialka is with Dept. of Agricultural and Biological Engineering, and authors Bialka and Demirci are with The Huck Inst. of Life Sciences, The Pennsylvania State Univ., Univ. Park, PA 16802, U.S.A. Direct inquiries to author Demirci (E-mail: demirci@psu.edu).
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  • A. Demirci

    1. Author Bialka is with Dept. of Agricultural and Biological Engineering, and authors Bialka and Demirci are with The Huck Inst. of Life Sciences, The Pennsylvania State Univ., Univ. Park, PA 16802, U.S.A. Direct inquiries to author Demirci (E-mail: demirci@psu.edu).
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Abstract

ABSTRACT:  Efficacy of gaseous ozone, aqueous ozone, and pulsed UV-light was evaluated for the purpose of decontaminating blueberries artificially contaminated with either Escherichia coli O157:H7 or Salmonella. Blueberries were exposed to 4 different gaseous ozone treatments: continuous ozone exposure, pressurized ozone exposure, and 2 combined treatments. Maximum reductions of Salmonella and E. coli O157:H7 after 64-min pressurized or 64-min continuous exposure were 3.0 and 2.2 log10 CFU/g, respectively. Aqueous ozone experiments were conducted at 20 °C and 4 °C and zero plate counts were observed for E. coli O157:H7 and Salmonella after 64 min of ozone exposure at 20 °C. Finally, pulsed UV-light was evaluated at 3 different distances from the light. Maximum reductions of 4.3 and 2.9 log10 CFU/g were observed at 8 cm from the light after 60 s of treatment for Salmonella and E. coli O157:H7, respectively. A sensory analysis as well as color analysis was performed on blueberries from each treatment agent; neither analysis detected a difference between treated and untreated blueberries. The results presented in this study indicate that ozone and pulsed UV-light are good candidates for decontamination of blueberries.

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