Decontamination of Escherichia coli O157:H7 and Salmonella enterica on blueberries using ozone and pulsed UV-light.
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 log(10) CFU/g, respectively. Aqueous ozone experiments were conducted at 20 degrees C and 4 degrees C and zero plate counts were observed for E. coli O157:H7 and Salmonella after 64 min of ozone exposure at 20 degrees C. Finally, pulsed UV-light was evaluated at 3 different distances from the light. Maximum reductions of 4.3 and 2.9 log(10) 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.
Dept. of Agricultural and Biological Engineering, and The Huck Inst. of Life Sciences, The Pennsylvania State Univ., Univ. Park, PA 16802, USA.
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Bialka
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Demirci
D000704:Analysis of Variance; D029798:Blueberry Plants / Q000187:drug effects / Q000382:microbiology* / Q000528:radiation effects; D015169:Colony Count, Microbial; D003116:Color; D003258:Consumer Behavior; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D005506:Food Contamination / Q000517:prevention & control*; D005511:Food Handling / Q000379:methods; D005514:Food Irradiation / Q000379:methods; D005516:Food Microbiology; D006801:Humans; D010083:Oxidants, Photochemical / Q000494:pharmacology; D010126:Ozone / Q000494:pharmacology*; D019779:Salmonella enterica / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D012677:Sensation / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome; D014466:Ultraviolet Rays
D010083:Oxidants, Photochemical; D010126:Ozone