Cronobacter Support
04-27-2009, 09:52 AM
1st International Conference on Cronobacter Poster Abstract 10
Comparison of the ISO/TS 22964 procedure with a new one-broth strategy for Cronobacter spp. detection in environmental and product samples
The current ISO standard method for detection of Enterobacteriaceae (21528-1:2004) includes enrichment in EE broth, which has been shown to be inhibitory to some members of this family, notably Cronobacter spp. A shortened procedure omitting the EE broth has been proposed (Joosten et al. 2008), however competition from Gram-positive flora may be detrimental to the effective recovery of low levels of target organisms in some sample matrices. In a recently finished study we investigated novel cost effective modifications, designed to improve ISO 21528-1:2004 for the detection of Enterobacteriaceae by a one broth strategy. Supplementation of buffered peptone water (BPW) with 8-hydroxyquinoline, ammonium iron(III) citrate, sodium deoxycholate and sodium pyruvate (BPW-S) improved the recovery of Enterobacteriaceae from artificially and naturally contaminated samples. The Enterobacteriaceae strains chosen included 16 Cronobacter spp. strains, and especially 9 strains that had been previously found to be particularly sensitive to selective agents used in microbiological growth media. In this study we are comparing the ISO/TS 22964 procedure, the Cronobacter screening broth (CSB) method (Iversen et al. 2008) as well as the new one broth strategy (BPW-S) for Cronobacter spp. detection in different samples from a PIF factory site. Samples divided into 55 finished products (PIF), and 10 supplementary food samples. 10g sample sizes were used, and dilution in BPW and BPW-S was at 1/10. All samples were pre-enriched for 24 h at 37°C. For the one broth strategy, the enriched samples (BPW-S) were streaked directly onto the modified version of Chromogenic E. sakazakii agar - DFI formulation (mDFI; Oxoid Ltd., Basingstoke, UK).
Nicole Giezendanner1, Patrick Druggan2, Carol Iversen3, Peter Stephens 2 and Roger Stephan1
1Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, CH-8057, Zürich, Switzerland. 2Oxoid Ltd., Thermo Fisher Scientific, Basingstoke, Hampshire, RG24 8PW, UK.3 Centre for Food Safety, School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
Comparison of the ISO/TS 22964 procedure with a new one-broth strategy for Cronobacter spp. detection in environmental and product samples
The current ISO standard method for detection of Enterobacteriaceae (21528-1:2004) includes enrichment in EE broth, which has been shown to be inhibitory to some members of this family, notably Cronobacter spp. A shortened procedure omitting the EE broth has been proposed (Joosten et al. 2008), however competition from Gram-positive flora may be detrimental to the effective recovery of low levels of target organisms in some sample matrices. In a recently finished study we investigated novel cost effective modifications, designed to improve ISO 21528-1:2004 for the detection of Enterobacteriaceae by a one broth strategy. Supplementation of buffered peptone water (BPW) with 8-hydroxyquinoline, ammonium iron(III) citrate, sodium deoxycholate and sodium pyruvate (BPW-S) improved the recovery of Enterobacteriaceae from artificially and naturally contaminated samples. The Enterobacteriaceae strains chosen included 16 Cronobacter spp. strains, and especially 9 strains that had been previously found to be particularly sensitive to selective agents used in microbiological growth media. In this study we are comparing the ISO/TS 22964 procedure, the Cronobacter screening broth (CSB) method (Iversen et al. 2008) as well as the new one broth strategy (BPW-S) for Cronobacter spp. detection in different samples from a PIF factory site. Samples divided into 55 finished products (PIF), and 10 supplementary food samples. 10g sample sizes were used, and dilution in BPW and BPW-S was at 1/10. All samples were pre-enriched for 24 h at 37°C. For the one broth strategy, the enriched samples (BPW-S) were streaked directly onto the modified version of Chromogenic E. sakazakii agar - DFI formulation (mDFI; Oxoid Ltd., Basingstoke, UK).
Nicole Giezendanner1, Patrick Druggan2, Carol Iversen3, Peter Stephens 2 and Roger Stephan1
1Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, CH-8057, Zürich, Switzerland. 2Oxoid Ltd., Thermo Fisher Scientific, Basingstoke, Hampshire, RG24 8PW, UK.3 Centre for Food Safety, School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.