Prevention of Escherichia coli cross-contamination by different commercial sanitizers during washing of fresh-cut lettuce

Int J Food Microbiol. 2009 Jul 31;133(1-2):167-71. doi: 10.1016/j.ijfoodmicro.2009.05.017. Epub 2009 May 22.

Abstract

The efficacy of fresh-cut produce sanitizers has mainly been evaluated by measuring microbial reductions on produce. However, its suitability to ensure that pathogens are rapidly killed avoiding cross-contamination of subsequent product also needs to be considered. The efficacy of chlorine, Tsunami, Citrox and Purac on non pathogenic Escherichia coli reductions in processing water and on fresh-cut lettuce were studied. Selection of minimum effective doses was carried out in processing water, which contained a chemical oxygen demand (COD) within the range of 700-1000 mg/l and a total mesophilic load of about 7 log CFU/ml. The processing water was inoculated with two inoculum levels (3 and 5 log CFU/ml). It was observed that 40 mg/l of chlorine and 500 mg/l of Tsunami were effective in reducing the inoculum levels in the processing water to the detection limit (5 and 4 log units). However, Citrox and Purac were not effective in reducing E. coli population even at the highest manufacturer's recommended doses. Evaluation of cross-contamination in fresh-cut lettuce was carried out by measuring E. coli transfer from inoculated (~5 log CFU/g) to uninoculated lettuce after washing the contaminated product in the water containing different sanitizing agents. Chlorine and Tsunami were able to inactivate E. coli in wash water, avoiding cross-contamination between contaminated and non-contaminated product. However, Citrox and Purac at the recommended doses did not prevent transfer of E. coli cells between inoculated and uninoculated fresh-cut lettuce and therefore indicating cross-contamination. The results obtained show that chlorine and Tsunami are recommended as water disinfection agents preventing E. coli cross-contamination of produce during processing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chlorine
  • Colony Count, Microbial
  • Consumer Product Safety
  • Disinfectants*
  • Disinfection / methods*
  • Escherichia coli / growth & development*
  • Food Contamination / prevention & control*
  • Food Microbiology*
  • Food-Processing Industry
  • Humans
  • Lactuca / microbiology*
  • Peracetic Acid
  • Water Microbiology*

Substances

  • Disinfectants
  • Chlorine
  • Peracetic Acid