The detection of non-O157 E. coli in food by immunomagnetic separation

M. Drysdale, Marion MacRae, T. M. Reid, Norval James Colin Strachan, Iain D Ogden

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Aims: To compare immunomagnetic separation (IMS) protocols (enrichment media and temperature) for the isolation of Escherichia coli serotypes O26 and O111 from four different foods.

Methods and Results: Foods (minced beef, cheese, apple juice and pepperoni) spiked with low numbers (<100 g(-1)) of stressed nalidixic mutant E. coli serotypes O26 and O111 were enriched in media based on buffered peptone water (BPW), tryptone soya and EC broths incubated at temperatures of 37 and 42degreesC to optimize the IMS technique. BPW enrichments gave increased recoveries of both serotypes compared with tryptone soya and EC broths. Elevated temperatures of incubation at 42degreesC were superior to 37degreesC.

Conclusions: Positive detection of low numbers of stressed target pathogens in all replicate tests was only possible using BPW enrichments. The majority of tests from alternative enrichments resulted in zero or single colonies recovered post-IMS.

Significance and Impact of the Study: The optimum IMS protocol would improve isolation rates of E. coli O26 and O111 from foods and lead to increased safety for the consumer. Sub-optimal IMS protocols could lead to foods being incorrectly labelled free from these pathogens.

Original languageEnglish
Pages (from-to)220-224
Number of pages4
JournalJournal of Applied Microbiology
Volume97
Issue number1
DOIs
Publication statusPublished - 2004

Keywords

  • E. coli O26
  • E. coli O111
  • immunomagnetic separation
  • methodology
  • SHIGA-LIKE TOXIN
  • HUMAN INFECTIONS
  • ISOLATION MEDIA
  • BOVINE FECES
  • O157
  • OPTIMIZATION
  • ENUMERATION
  • ENRICHMENT
  • OUTBREAK
  • STRAINS

Cite this

The detection of non-O157 E. coli in food by immunomagnetic separation. / Drysdale, M.; MacRae, Marion; Reid, T. M.; Strachan, Norval James Colin; Ogden, Iain D.

In: Journal of Applied Microbiology, Vol. 97, No. 1, 2004, p. 220-224.

Research output: Contribution to journalArticle

@article{331d0771efa34d9685b7eaa0cb83e001,
title = "The detection of non-O157 E. coli in food by immunomagnetic separation",
abstract = "Aims: To compare immunomagnetic separation (IMS) protocols (enrichment media and temperature) for the isolation of Escherichia coli serotypes O26 and O111 from four different foods.Methods and Results: Foods (minced beef, cheese, apple juice and pepperoni) spiked with low numbers (<100 g(-1)) of stressed nalidixic mutant E. coli serotypes O26 and O111 were enriched in media based on buffered peptone water (BPW), tryptone soya and EC broths incubated at temperatures of 37 and 42degreesC to optimize the IMS technique. BPW enrichments gave increased recoveries of both serotypes compared with tryptone soya and EC broths. Elevated temperatures of incubation at 42degreesC were superior to 37degreesC.Conclusions: Positive detection of low numbers of stressed target pathogens in all replicate tests was only possible using BPW enrichments. The majority of tests from alternative enrichments resulted in zero or single colonies recovered post-IMS.Significance and Impact of the Study: The optimum IMS protocol would improve isolation rates of E. coli O26 and O111 from foods and lead to increased safety for the consumer. Sub-optimal IMS protocols could lead to foods being incorrectly labelled free from these pathogens.",
keywords = "E. coli O26, E. coli O111, immunomagnetic separation, methodology, SHIGA-LIKE TOXIN, HUMAN INFECTIONS, ISOLATION MEDIA, BOVINE FECES, O157, OPTIMIZATION, ENUMERATION, ENRICHMENT, OUTBREAK, STRAINS",
author = "M. Drysdale and Marion MacRae and Reid, {T. M.} and Strachan, {Norval James Colin} and Ogden, {Iain D}",
year = "2004",
doi = "10.1111/j.1365-2672.2004.02301.x",
language = "English",
volume = "97",
pages = "220--224",
journal = "Journal of Applied Microbiology",
issn = "1364-5072",
publisher = "Wiley-Blackwell",
number = "1",

}

TY - JOUR

T1 - The detection of non-O157 E. coli in food by immunomagnetic separation

AU - Drysdale, M.

AU - MacRae, Marion

AU - Reid, T. M.

AU - Strachan, Norval James Colin

AU - Ogden, Iain D

PY - 2004

Y1 - 2004

N2 - Aims: To compare immunomagnetic separation (IMS) protocols (enrichment media and temperature) for the isolation of Escherichia coli serotypes O26 and O111 from four different foods.Methods and Results: Foods (minced beef, cheese, apple juice and pepperoni) spiked with low numbers (<100 g(-1)) of stressed nalidixic mutant E. coli serotypes O26 and O111 were enriched in media based on buffered peptone water (BPW), tryptone soya and EC broths incubated at temperatures of 37 and 42degreesC to optimize the IMS technique. BPW enrichments gave increased recoveries of both serotypes compared with tryptone soya and EC broths. Elevated temperatures of incubation at 42degreesC were superior to 37degreesC.Conclusions: Positive detection of low numbers of stressed target pathogens in all replicate tests was only possible using BPW enrichments. The majority of tests from alternative enrichments resulted in zero or single colonies recovered post-IMS.Significance and Impact of the Study: The optimum IMS protocol would improve isolation rates of E. coli O26 and O111 from foods and lead to increased safety for the consumer. Sub-optimal IMS protocols could lead to foods being incorrectly labelled free from these pathogens.

AB - Aims: To compare immunomagnetic separation (IMS) protocols (enrichment media and temperature) for the isolation of Escherichia coli serotypes O26 and O111 from four different foods.Methods and Results: Foods (minced beef, cheese, apple juice and pepperoni) spiked with low numbers (<100 g(-1)) of stressed nalidixic mutant E. coli serotypes O26 and O111 were enriched in media based on buffered peptone water (BPW), tryptone soya and EC broths incubated at temperatures of 37 and 42degreesC to optimize the IMS technique. BPW enrichments gave increased recoveries of both serotypes compared with tryptone soya and EC broths. Elevated temperatures of incubation at 42degreesC were superior to 37degreesC.Conclusions: Positive detection of low numbers of stressed target pathogens in all replicate tests was only possible using BPW enrichments. The majority of tests from alternative enrichments resulted in zero or single colonies recovered post-IMS.Significance and Impact of the Study: The optimum IMS protocol would improve isolation rates of E. coli O26 and O111 from foods and lead to increased safety for the consumer. Sub-optimal IMS protocols could lead to foods being incorrectly labelled free from these pathogens.

KW - E. coli O26

KW - E. coli O111

KW - immunomagnetic separation

KW - methodology

KW - SHIGA-LIKE TOXIN

KW - HUMAN INFECTIONS

KW - ISOLATION MEDIA

KW - BOVINE FECES

KW - O157

KW - OPTIMIZATION

KW - ENUMERATION

KW - ENRICHMENT

KW - OUTBREAK

KW - STRAINS

U2 - 10.1111/j.1365-2672.2004.02301.x

DO - 10.1111/j.1365-2672.2004.02301.x

M3 - Article

VL - 97

SP - 220

EP - 224

JO - Journal of Applied Microbiology

JF - Journal of Applied Microbiology

SN - 1364-5072

IS - 1

ER -