Abstract

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 10⁶ 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/cm² 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.

Links

Publisher Full Text

Authors

Zhou B, Luo Y, Millner P, Feng H

Institution

Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.

Source

Journal of food protection 75:3 2012 Mar pg 563-6

MeSH

Bacterial Adhesion
Chlorine
Colony Count, Microbial
Consumer Product Safety
Cooking and Eating Utensils
Escherichia coli O157
Food Contamination
Humans
Lettuce
Ultrasonics

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22410232