Sanitation and design of lettuce coring knives for minimizing Escherichia coli O157:H7 contamination

Bin Zhou, Yaguang Luo, Patricia Millner, Hao Feng

Research output: Contribution to journalArticlepeer-review


This study was undertaken to examine the effect of ultrasound in combination with chlorine on the reduction of Escherichia coli O157:H7 populations on lettuce coring knives. Two new coring devices designed to mitigate pathogen attachment were fabricated and evaluated. The coring rings of the knives were dip inoculated with soil slurry containing 10 6 E. coli cells and treated with chlorinated water with and without ultrasonication for 30, 60, and 120 s. The rough welding joints on currently used in-field lettuce coring knives provided a site conducive to bacterial attachment and resistant to cell removal during sanitation treatment. The two modified coring knives harbored significantly fewer E. coli cells than did the currently used commercial model, and the efficacy of the disinfection treatment was high (P < 0.05). Ultrasound treatment reduced the E. coli O157:H7 counts to below the detection limit of 1.10 log CFU/cm 2 at both the coring ring blade and welding joint within 30 s in 1 ppm of chlorinated water. The redesigned coring knives and an ultrasound plus chlorine combination treatment may provide practical options for minimizing the microbial safety hazards of lettuce processed by core-in-field operations.

Original languageEnglish (US)
Pages (from-to)563-566
Number of pages4
JournalJournal of Food Protection
Issue number3
StatePublished - Mar 1 2012

ASJC Scopus subject areas

  • Food Science
  • Microbiology


Dive into the research topics of 'Sanitation and design of lettuce coring knives for minimizing Escherichia coli O157:H7 contamination'. Together they form a unique fingerprint.

Cite this