Efficacy of ozone in killing Listeria monocytogenes on alfalfa seeds and sprouts and effects on sensory quality of sprouts

W. N. Wade, A. J. Scouten, K. H. McWatters, R. L. Wick, A. Demirci, W. F. Fett, L. R. Beuchat

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

A study was done to determine the efficacy of aqueous ozone treatment in killing Listeria monocytogenes on inoculated alfalfa seeds and sprouts. Reductions in populations of naturally occurring aerobic microorganisms on sprouts and changes in the sensory quality of sprouts were also determined. The treatment (10 or 20 min) of seeds in water (4°C) containing an initial concentration of 21.8 ± 0.1 μg/ml of ozone failed to cause a significant (P ≤ 0.05) reduction in populations of L. monocytogenes. The continuous sparging of seeds with ozonated water (initial ozone concentration of 21.3 ± 0.2 μg/ml) for 20 min significantly reduced the population by 1.48 log10 CFU/g. The treatment (2 min) of inoculated alfalfa sprouts with water containing 5.0 ± 0.5, 9.0 ± 0.5, or 23.2 ± 1.6 μg/ml of ozone resulted in significant (P ≤ 0.05) reductions of 0.78, 0.81, and 0.91 log10 CFU/g, respectively, compared to populations detected on sprouts treated with water. Treatments (2 min) with up to 23.3 ± 1.6 μg/ml of ozone did not significantly (P > 0.05) reduce populations of aerobic naturally occurring microorganisms. The continuous sparging of sprouts with ozonated water for 5 to 20 min caused significant reductions in L. monocytogenes and natural microbiota compared to soaking in water (control) but did not enhance the lethality compared to the sprouts not treated with continuous sparging. The treatment of sprouts with ozonated water (20.0 μg/ml) for 5 or 10 min caused a significant deterioration in the sensory quality during subsequent storage at 4°C for 7 to 11 days. Scanning electron microscopy of uninoculated alfalfa seeds and sprouts showed physical damage, fungal and bacterial growth, and biofilm formation that provide evidence of factors contributing to the difficulty of killing microorganisms by treatment with ozone and other sanitizers.

Original languageEnglish (US)
Pages (from-to)44-51
Number of pages8
JournalJournal of food protection
Volume66
Issue number1
DOIs
StatePublished - Jan 1 2003

All Science Journal Classification (ASJC) codes

  • Food Science
  • Microbiology

Fingerprint Dive into the research topics of 'Efficacy of ozone in killing Listeria monocytogenes on alfalfa seeds and sprouts and effects on sensory quality of sprouts'. Together they form a unique fingerprint.

  • Cite this