Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

Record number 495754
Title Improving the enrichment procedure for the detection of low contamination levels of Shiga Toxin-producing E. coli in sprouts
Author(s) Margot, H.; Zwietering, M.H.; Joosten, H.M.L.J.; Stephan, R.
Event IAFP European Symposium on Food Safety, Cardiff, Wales, Cardiff, 2015-04-20/2015-04-22
Department(s) VLAG
Food Microbiology Laboratory
Publication type Abstract in scientific journal or proceedings
Publication year 2015
Abstract lntroduction: In 2011 , an outbreak of Shiga Toxin-producing E. coli (STEG) infections in Germany was caused by a strain belonging to serotype 0104:H4. Epidemiological data linked the outbreak to the consumption of sprouts; even so the pathogen could never be detected in sprout samples nor seeds. For STEG detection in sprouts, JSO/TS 13136 prescribes an unselective enrichment step in BPW tor 24 h at 37°G, followed by a PCR detection of stx genes.
Purpose: The purpose of this study was to assess and improve ISO enrichment procedure for the detection of low STEG levels in sprouts.
Methods: First, 10 g of soy sprouts were spiked with 10-100 CFU of stressed STEC and enriched (1:10) overnight in BPW (ISO procedure). The presence of stx1 and stx2 in the enriched samples was tested with a real time multiplex PCR
system. In a second step, six enrichment broths used for the enrichment of Enterobacteriaceae were compared for their ability to promote growth (at 37°G and 42°C) of six stressed and unstressed STEG strains of different serotypes. Based on the results, some of these media were further tested with spiked sprouts.
Results: The experiments with sprouts spiked with low levels of stressed STEC, enriched in BPW, showed that contamination levels below 103 CFU per 10 g could not be reliably detected with PCR. The main reason tor the detection failure is probably the very high levels of the Gram negative background flora (107 CFU/g) in sprouts. The evaluation of selected unstressed STEC strains showed no growth differences between the strains at 37°C and 42°C in EE broth, BGB broth and BPW. Stressed strains, however, showed a longer lag time tor both 37°C and 42°C and a greater strain variation.
Significance: An improved enrichment procedure tor the detection of STEG will significantly strengthen food safety of sprouts.
There are no comments yet. You can post the first one!
Post a comment
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.